Merge pull request 'diplomail (Stage A→D): backend in-game diplomatic mail' (#10) from feature/diplomail-backend into development

Closes the documentation gaps from the freshly-audited diplomail
implementation. FUNCTIONAL.md gains a §11 "Diplomatic mail" with
the full user-facing story across all five stages, mirrored into
FUNCTIONAL_ru.md as the project conventions require. A new
backend/docs/diplomail-translator-setup.md captures the
LibreTranslate operational recipe (Docker image, env wiring,
manual smoke test, troubleshooting). The package README gains a
"Multi-instance posture" note documenting the deliberate absence
of FOR UPDATE in the worker pickup query — single-instance is
safe today; multi-instance scaling will revisit the claim
mechanism.

Two small edge-case tests round things out: malformed
LibreTranslate response bodies (single string, short array,
empty array, missing field) must surface as errors so the worker
falls back instead of crashing; and an empty translation queue
must produce zero events on three consecutive Worker.Tick calls.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/settings.json

@@ -1,28 +1,23 @@
 {
-    "sandbox": {
+  "permissions": {
-        "network": {
+    "allow": [],
-            "allowLocalBinding": true,
+    "defaultMode": "default"
-            "allowUnixSockets": ["/Users/id/.colima/default/docker.sock"],
+  },
-            "allowedDomains": [
+  "sandbox": {
-                "github.com",
+    "network": {
-                "registry.npmjs.org",
+      "allowedDomains": [
-                "*.npmjs.org",
+        "github.com",
-                "docker.com",
+        "registry.npmjs.org",
-                "docker.io",
+        "*.npmjs.org",
-                "gcr.io",
+        "docker.com",
-                "*.golang.org"
+        "docker.io",
-            ]
+        "gcr.io",
-        }
+        "*.golang.org"
-    },
+      ],
-    "enabledPlugins": {
+      "allowUnixSockets": [
-        "gopls-lsp@claude-plugins-official": true,
+        "/var/run/docker.sock"
-        "context7@claude-plugins-official": true
+      ],
-    },
+      "allowLocalBinding": true
-    "permissions": {
-        "defaultMode": "plan",
-        "allow": [
-            "mcp__context7__resolve-library-id",
-            "mcp__context7__get-library-docs"
-        ]
     }
-}
+  }
+}

.gitattributes

@@ -0,0 +1,5 @@
+*.wasm binary
+*.ts linguist-language=TypeScript
+*.ts linguist-detectable=true
+*.ts linguist-vendored=false
+*.ts linguist-generated=false

.gitea/workflows/deploy-prod.yaml

@@ -0,0 +1,31 @@
+name: Deploy · Prod
+
+# Placeholder for the production rollout workflow. Today it only proves
+# the manual entry point works; the actual `docker save | ssh prod
+# docker load` + remote `docker compose up -d` pipeline is wired in
+# once the production host, SSH credentials, and DNS are decided.
+
+on:
+  workflow_dispatch:
+    inputs:
+      image_tag:
+        description: "Image tag to deploy (commit-<sha12>, produced by prod-build.yaml)"
+        required: true
+        type: string
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Announce target
+        run: |
+          echo "Would deploy image tag: ${{ inputs.image_tag }}"
+          echo "TODO:"
+          echo "  1. Download galaxy-images-${{ inputs.image_tag }} from prod-build artifacts."
+          echo "  2. scp the .tar.gz bundles to the production host."
+          echo "  3. ssh prod 'docker load -i ...' for backend / gateway / engine."
+          echo "  4. ssh prod 'docker compose -f /opt/galaxy/docker-compose.yml up -d'."
+          echo "  5. Probe https://api.galaxy.com/healthz and roll back on failure."

.gitea/workflows/dev-deploy.yaml

@@ -0,0 +1,117 @@
+name: Deploy · Dev
+
+# Builds the Galaxy stack and (re)deploys it into the long-lived dev
+# environment on the host running this Gitea Actions runner. Triggered
+# on every merge into `development`. Branch protections on `development`
+# guarantee the commit already passed `go-unit`, `ui-test`, and
+# `integration` as part of the PR that produced this push, so this
+# workflow does not re-run those tests — it focuses on packaging and
+# rollout.
+
+on:
+  push:
+    branches:
+      - development
+    paths:
+      - 'backend/**'
+      - 'gateway/**'
+      - 'game/**'
+      - 'pkg/**'
+      - 'ui/**'
+      - 'go.work'
+      - 'go.work.sum'
+      - 'tools/dev-deploy/**'
+      - '.gitea/workflows/dev-deploy.yaml'
+      - '!**/*.md'
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.work
+          cache: true
+
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 11.0.7
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+          cache-dependency-path: ui/pnpm-lock.yaml
+
+      - name: Install UI dependencies
+        working-directory: ui
+        run: pnpm install --frozen-lockfile
+
+      - name: Build UI frontend
+        working-directory: ui/frontend
+        env:
+          VITE_GATEWAY_BASE_URL: https://api.galaxy.lan
+        run: |
+          # The response-signing public key is committed in
+          # `.env.development` alongside its private counterpart in
+          # `tools/local-dev/keys/`. Pull it from there at build time so
+          # the production-mode bundle ships the same key the dev
+          # gateway uses to sign.
+          export VITE_GATEWAY_RESPONSE_PUBLIC_KEY="$(grep -E '^VITE_GATEWAY_RESPONSE_PUBLIC_KEY=' .env.development | cut -d= -f2)"
+          pnpm build
+
+      - name: Build galaxy-engine image
+        working-directory: ${{ gitea.workspace }}
+        run: |
+          docker build \
+            -t galaxy-engine:dev \
+            -f game/Dockerfile \
+            .
+
+      - name: Build backend + gateway images
+        working-directory: tools/dev-deploy
+        run: |
+          docker compose build galaxy-backend galaxy-api
+
+      - name: Seed UI volume
+        run: |
+          docker volume create galaxy-dev-ui-dist >/dev/null
+          docker run --rm \
+            -v galaxy-dev-ui-dist:/dst \
+            -v "${{ gitea.workspace }}/ui/frontend/build:/src:ro" \
+            alpine sh -c 'rm -rf /dst/* /dst/.??* 2>/dev/null; cp -a /src/. /dst/'
+
+      - name: Bring up the stack
+        working-directory: tools/dev-deploy
+        run: |
+          # Resolve in the shell, not in YAML expressions — `env.HOME`
+          # is empty at the workflow-evaluation stage.
+          export GALAXY_DEV_GAME_STATE_DIR="$HOME/.galaxy-dev/game-state"
+          mkdir -p "$GALAXY_DEV_GAME_STATE_DIR"
+          docker compose up -d --wait --remove-orphans
+
+      - name: Probe the stack
+        run: |
+          set -e
+          # Use --resolve so the probe goes through the same routing as
+          # a browser on the host: the host Caddy on :443 (which has
+          # `tls internal`) terminates and forwards into the edge
+          # network. We accept the host's internal CA via -k because
+          # the runner image has no reason to trust it.
+          curl -sk --max-time 10 https://api.galaxy.lan/healthz \
+            | tee /tmp/healthz
+          test -s /tmp/healthz
+          curl -sk --max-time 10 -o /dev/null -w '%{http_code}\n' \
+            https://www.galaxy.lan/ | tee /tmp/www_status
+          grep -qE '^(200|304)$' /tmp/www_status

.gitea/workflows/go-unit.yaml

@@ -0,0 +1,78 @@
+name: Tests · Go
+
+# Fast unit tests for the Go side of the monorepo. Runs on every push
+# and pull request whose path filter matches a Go source directory.
+# The integration suite (testcontainers-driven, slow) lives in
+# `integration.yaml` and only fires for PRs into `development`/`main`
+# and pushes to `development`.
+
+on:
+  push:
+    paths:
+      - 'backend/**'
+      - 'gateway/**'
+      - 'game/**'
+      - 'pkg/**'
+      - 'ui/core/**'
+      - 'go.work'
+      - 'go.work.sum'
+      - '.gitea/workflows/go-unit.yaml'
+      - '!**/*.md'
+  pull_request:
+    paths:
+      - 'backend/**'
+      - 'gateway/**'
+      - 'game/**'
+      - 'pkg/**'
+      - 'ui/core/**'
+      - 'go.work'
+      - 'go.work.sum'
+      - '.gitea/workflows/go-unit.yaml'
+      - '!**/*.md'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.work
+          cache: true
+
+      - name: Run Go tests
+        # client/ is the deprecated Fyne client; excluded from CI per
+        # ui/PLAN.md §74. -count=1 disables Go's test cache so a green
+        # run never depends on a previous runner's cached state. The
+        # backend suite is run with -p 1 because most backend packages
+        # spawn their own Postgres testcontainer, and parallel
+        # Postgres bootstraps starve each other on a constrained
+        # runner. pkg modules are listed one by one because ./pkg/...
+        # does not recurse across the independent go.work modules
+        # under pkg/.
+        run: |
+          go test -count=1 -p 1 ./backend/...
+          go test -count=1 \
+            ./gateway/... \
+            ./game/... \
+            ./ui/core/... \
+            ./pkg/calc/... \
+            ./pkg/connector/... \
+            ./pkg/cronutil/... \
+            ./pkg/error/... \
+            ./pkg/geoip/... \
+            ./pkg/model/... \
+            ./pkg/postgres/... \
+            ./pkg/redisconn/... \
+            ./pkg/schema/... \
+            ./pkg/storage/... \
+            ./pkg/transcoder/... \
+            ./pkg/util/...

.gitea/workflows/integration.yaml

@@ -0,0 +1,65 @@
+name: Tests · Integration
+
+# Full integration suite (testcontainers-driven, ~5–10 minutes). Heavy
+# enough that we do not run it on every push to a feature branch — only
+# when there is an open PR aimed at `development`/`main`, or after a
+# merge into `development`. The unit jobs (`go-unit.yaml`,
+# `ui-test.yaml`) keep guarding fast feedback on every push.
+
+on:
+  pull_request:
+    branches:
+      - development
+      - main
+    paths:
+      - 'backend/**'
+      - 'gateway/**'
+      - 'game/**'
+      - 'pkg/**'
+      - 'ui/core/**'
+      - 'integration/**'
+      - 'go.work'
+      - 'go.work.sum'
+      - '.gitea/workflows/integration.yaml'
+      - '!**/*.md'
+  push:
+    branches:
+      - development
+    paths:
+      - 'backend/**'
+      - 'gateway/**'
+      - 'game/**'
+      - 'pkg/**'
+      - 'ui/core/**'
+      - 'integration/**'
+      - 'go.work'
+      - 'go.work.sum'
+      - '.gitea/workflows/integration.yaml'
+      - '!**/*.md'
+
+jobs:
+  integration:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.work
+          cache: true
+
+      - name: Run integration suite
+        # `make integration` precleans leftover docker-compose state and
+        # then runs every test under integration/ serially (-p=1
+        # -parallel=1, 15-minute per-test timeout). Testcontainers
+        # reaches the host's docker daemon via the socket Gitea exposes
+        # to the runner; the workflow inherits the same access the
+        # runner has.
+        run: make -C integration integration

.gitea/workflows/prod-build.yaml

@@ -0,0 +1,116 @@
+name: Build · Prod
+
+# Builds the production-grade Docker images and the UI bundle on every
+# merge into `main`, then saves the artifacts so a future
+# `deploy-prod.yaml` run can ship them to the production host. This
+# workflow does not deploy anything by itself — production rollout is
+# strictly manual (workflow_dispatch on `deploy-prod.yaml`).
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'backend/**'
+      - 'gateway/**'
+      - 'game/**'
+      - 'pkg/**'
+      - 'ui/**'
+      - 'go.work'
+      - 'go.work.sum'
+      - '.gitea/workflows/prod-build.yaml'
+      - '!**/*.md'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.work
+          cache: true
+
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 11.0.7
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+          cache-dependency-path: ui/pnpm-lock.yaml
+
+      - name: Resolve image tag
+        id: tag
+        run: |
+          short_sha=$(git rev-parse --short=12 HEAD)
+          echo "tag=commit-${short_sha}" >>"$GITHUB_OUTPUT"
+
+      - name: Build backend image
+        run: |
+          docker build \
+            -t "galaxy/backend:${{ steps.tag.outputs.tag }}" \
+            -f backend/Dockerfile \
+            .
+
+      - name: Build gateway image
+        run: |
+          docker build \
+            -t "galaxy/gateway:${{ steps.tag.outputs.tag }}" \
+            -f gateway/Dockerfile \
+            .
+
+      - name: Build engine image
+        run: |
+          docker build \
+            -t "galaxy/game-engine:${{ steps.tag.outputs.tag }}" \
+            -f game/Dockerfile \
+            .
+
+      - name: Install UI dependencies
+        working-directory: ui
+        run: pnpm install --frozen-lockfile
+
+      - name: Build UI bundle
+        working-directory: ui/frontend
+        env:
+          VITE_GATEWAY_BASE_URL: https://api.galaxy.com
+        run: |
+          # Production response-signing public key is not in the repo
+          # yet (the dev key in `tools/local-dev/keys/` is for dev
+          # only). When real prod keys exist, source them from a Gitea
+          # Actions secret and set VITE_GATEWAY_RESPONSE_PUBLIC_KEY
+          # here. Until then the prod bundle compiles with the dev
+          # key as a placeholder so the artifact exists.
+          export VITE_GATEWAY_RESPONSE_PUBLIC_KEY="$(grep -E '^VITE_GATEWAY_RESPONSE_PUBLIC_KEY=' .env.development | cut -d= -f2)"
+          pnpm build
+
+      - name: Save images as artifact bundles
+        run: |
+          mkdir -p artifacts
+          docker save "galaxy/backend:${{ steps.tag.outputs.tag }}" \
+            | gzip >"artifacts/backend-${{ steps.tag.outputs.tag }}.tar.gz"
+          docker save "galaxy/gateway:${{ steps.tag.outputs.tag }}" \
+            | gzip >"artifacts/gateway-${{ steps.tag.outputs.tag }}.tar.gz"
+          docker save "galaxy/game-engine:${{ steps.tag.outputs.tag }}" \
+            | gzip >"artifacts/game-engine-${{ steps.tag.outputs.tag }}.tar.gz"
+          tar -C ui/frontend -czf \
+            "artifacts/ui-dist-${{ steps.tag.outputs.tag }}.tar.gz" build
+
+      - name: Upload images
+        uses: actions/upload-artifact@v4
+        with:
+          name: galaxy-images-${{ steps.tag.outputs.tag }}
+          path: artifacts/*.tar.gz
+          retention-days: 30

.gitea/workflows/ui-test.yaml

@@ -0,0 +1,101 @@
+name: Tests · UI
+
+# UI-side unit and end-to-end tests (Vitest + Playwright). The Go side
+# of the workspace is tested in `go-unit.yaml`. Both workflows can run
+# in parallel for a push that touches Go and UI together.
+
+on:
+  push:
+    paths:
+      - 'ui/**'
+      - '.gitea/workflows/ui-test.yaml'
+      - '!**/*.md'
+  pull_request:
+    paths:
+      - 'ui/**'
+      - '.gitea/workflows/ui-test.yaml'
+      - '!**/*.md'
+
+# Playwright launches its own `pnpm dev` on :5173, and in host-mode
+# the runner shares the host's port namespace with every other job,
+# so two parallel ui-test runs collide on EADDRINUSE. Serialise via a
+# singleton concurrency group with queueing — new runs wait their
+# turn instead of cancelling the in-progress one. cancel-in-progress
+# is explicitly false because Gitea has shown spurious self-cancel
+# behaviour under cancel-in-progress: true even when no other run
+# shares the group.
+concurrency:
+  group: ui-test-singleton
+  cancel-in-progress: false
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          submodules: recursive
+
+      - name: Set up pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 11.0.7
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: pnpm
+          cache-dependency-path: ui/pnpm-lock.yaml
+
+      - name: Install npm dependencies
+        working-directory: ui
+        run: pnpm install --frozen-lockfile
+
+      - name: Install Playwright browsers
+        # `--with-deps` would shell out to `sudo apt-get install` for
+        # the system .so libraries, which the host-mode runner cannot
+        # run non-interactively. The host has the deps installed once,
+        # globally; we only need to fetch the browser binaries here.
+        # If a future run fails with missing libraries, install them
+        # on the host via `pnpm exec playwright install-deps` (one
+        # shot, requires sudo).
+        working-directory: ui/frontend
+        run: pnpm exec playwright install
+
+      - name: Run Vitest
+        working-directory: ui/frontend
+        run: pnpm test
+
+      - name: Clear stale Vite from :5173
+        # Defence in depth in case a previous job's webServer survived
+        # the concurrency-cancel — `pkill` does not fail when there is
+        # nothing to kill, and `fuser -k` cleans up anything else
+        # holding the port.
+        run: |
+          pkill -f 'vite dev' || true
+          fuser -k 5173/tcp 2>/dev/null || true
+
+      - name: Run Playwright
+        working-directory: ui/frontend
+        run: pnpm exec playwright test
+
+      - name: Upload Playwright report on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: playwright-report
+          path: ui/frontend/playwright-report/
+          retention-days: 14
+
+      - name: Upload Playwright traces on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: playwright-traces
+          path: ui/frontend/test-results/
+          retention-days: 14

.gitignore

@@ -1,3 +1,16 @@
 .codex
 .vscode/
-artifacts/
+artifacts/.claude/scheduled_tasks.lock
+
+# Per-developer Claude Code overrides. The committed
+# `.claude/settings.json` holds the shared project defaults;
+# `settings.local.json` is each developer's local override
+# (looser permissions, disabled sandbox) and must not be staged.
+.claude/settings.local.json
+
+# Per-developer Vite dotenv overrides. The committed
+# `ui/frontend/.env.development` ships sane defaults for the
+# `tools/local-dev/` stack; `.local` siblings stay personal and
+# unstaged.
+**/.env.local
+**/.env.*.local

CLAUDE.md

@@ -30,19 +30,71 @@ This repository hosts the Galaxy Game project.
 
 - `galaxy/<service>/PLAN.md` — staged implementation plan for the service.
   May be already complete and resides for historical reasons.
-- `galaxy/<service>/docs/` — per-stage decision records
+- `galaxy/<service>/docs/` — live topic-based documentation that's
-  (one file per decision, re-organized after full implementation
+  deeper than what fits in `README.md` (per-feature design notes,
-  of `PLAN.md`).
+  protocol specs, runbooks). Not stage-by-stage history.
 
-## Decision records when implementing stages from PLAN.md
+## Branching and CI flow
 
-- Stage-related discussion and decisions do NOT live in `README.md` or
+Branches:
-  `docs/ARCHITECTURE.md`. Those files describe the current state, not the history.
+
-- Each non-trivial decision gets its own `.md` under the module's `docs/`,
+- `main` — production-track. Direct pushes are disallowed; the only
-  referenced from the relevant `README.md`.
+  way in is a PR merge from `development`. A merge fires
-- Any agreement reached during interactive planning that is not obvious from
+  `prod-build.yaml` which packages the artifacts; production rollout
-  the code must be captured — either as a decision record or as an entry in
+  is manual through `deploy-prod.yaml`.
-  the module's README.
+- `development` — long-lived dev integration branch. Every merge into
+  it auto-deploys to the dev environment via `dev-deploy.yaml`
+  (reachable at `https://www.galaxy.lan` / `https://api.galaxy.lan`).
+- `feature/*` — short-lived branches off `development`. Merged back
+  via PR; only then do they reach the dev environment.
+
+Workflows in `.gitea/workflows/`:
+
+| File | Trigger | What it does |
+|------|---------|--------------|
+| `go-unit.yaml` | push + PR matching Go paths | Fast Go unit tests. |
+| `ui-test.yaml` | push + PR matching `ui/**` | Vitest + Playwright. |
+| `integration.yaml` | PR to `development`/`main`; push to `development` | testcontainers integration suite. |
+| `dev-deploy.yaml` | push to `development` | Build images + (re)deploy to `tools/dev-deploy/`. |
+| `prod-build.yaml` | push to `main` | Build prod images and `docker save` into artifacts. |
+| `deploy-prod.yaml` | `workflow_dispatch` | Manual rollout (placeholder until prod host exists). |
+
+## Per-stage CI gate
+
+Every completed stage from any `PLAN.md` (per-service or `ui/PLAN.md`)
+must be exercised on `gitea.lan` before being declared done. The
+short version:
+
+1. Commit the stage changes on the feature branch.
+2. `git push gitea …` to publish the branch.
+3. Poll the latest run in the Gitea UI (or the API) until it leaves
+   `running`. Inspect the log on failure.
+4. Only after every workflow that fired is `success` may the stage be
+   marked done in the corresponding `PLAN.md`.
+
+`tools/local-ci/` is now an opt-in fallback for testing workflow
+changes without `gitea.lan` (offline iterations, runner-isolation
+debugging). It is no longer required for the per-stage gate.
+
+## Decisions during stage implementation
+
+Stages from `PLAN.md` produce decisions. Those decisions never live in a
+separate per-decision history file. Instead, every non-obvious decision is
+baked back into the live state in three places:
+
+1. **The plan itself.** Update the relevant stage's text, acceptance
+   criteria, or targeted tests so it reflects what was decided. If
+   earlier already-implemented stages need to follow the new agreement,
+   correct their code, tests, and live docs in the same patch.
+2. **Later, not-yet-implemented stages.** When a decision affects later
+   stages — scope, dependencies, deliverables, or tests — update those
+   stages now, do not leave the future to re-derive them.
+3. **Live documentation.** Module `README.md`, project
+   `docs/ARCHITECTURE.md`, `docs/FUNCTIONAL.md` (with its
+   `docs/FUNCTIONAL_ru.md` mirror), the affected service `openapi.yaml`
+   or `*.proto`, and any topic doc under `galaxy/<service>/docs/` that
+   the decision touches. `README.md` and `ARCHITECTURE.md` always
+   describe current state, not the history of how it was reached.
 
 ## Scope of PLAN.md changes
 
@@ -82,8 +134,8 @@ details.
 The same behaviour is described in several parallel sources: code,
 `docs/ARCHITECTURE.md`, `docs/FUNCTIONAL.md` (with its Russian mirror
 `docs/FUNCTIONAL_ru.md`), the affected service `README.md`, the
-relevant `openapi.yaml` or `*.proto`, and the per-stage decision
+relevant `openapi.yaml` or `*.proto`, and the topic-based docs under
-records under `galaxy/<service>/docs/`. They must never disagree.
+`galaxy/<service>/docs/`. They must never disagree.
 
 - Any patch that changes user-visible behaviour, an API contract, or a
   cross-service flow updates every affected source in the same change
@@ -103,6 +155,22 @@ records under `galaxy/<service>/docs/`. They must never disagree.
   `docs/FUNCTIONAL_ru.md` (translate only the touched paragraphs).
   Skipping the mirror is treated as an incomplete patch.
 
+## Code compactness
+
+- Prefer compact code over speculative universality. Three similar
+  occurrences are not yet a pattern — wait for the third real caller
+  before extracting an abstraction.
+- Do not add seams, hooks, or configuration knobs for hypothetical
+  future requirements. If the next stage of `PLAN.md` will need
+  something, the next stage will add it.
+- A bug fix does not need surrounding cleanup; a one-shot operation
+  does not need a helper function; a single concrete value does not
+  need a parameter.
+- When the plan can be satisfied by reusing an existing function or
+  type, do that instead of introducing a new one.
+- This rule is about scope, not laziness — well-named identifiers,
+  precise types, and full test coverage stay non-negotiable.
+
 ## Dependencies
 
 - Before adding a new module, check its upstream repository for the latest

backend/PLAN.md

@@ -1,868 +0,0 @@
-# backend — Implementation Plan
-
-This plan has been already implemented and stays here for historical reasons.
-
-It should NOT be threated as source of truth for service functionality.
-
----
-
-## Summary
-
-This plan is the technical specification for implementing the
-consolidated Galaxy `backend` service. It is read together with
-`../docs/ARCHITECTURE.md` (architecture and security model) and
-`README.md` (module layout, configuration, operations).
-
-After reading those two documents and this plan, an implementing
-engineer should not need to ask architectural questions. Every stage is
-self-contained inside its domain area; stages run in order; each stage
-has explicit Critical files.
-
-The plan does not invent new domain concepts. It catalogues the work
-required to assemble what the architecture document already defines.
-
-## ~~Stage 1~~ — Repository cleanup
-
-This stage was implemented and marked as done.
-
-Goal: remove every module whose responsibility moves into `backend`,
-and prepare the workspace for the new module.
-
-Actions:
-
-1. `git rm -r authsession/ lobby/ mail/ notification/ gamemaster/
-   rtmanager/ geoprofile/ user/ integration/ pkg/redisconn/
-   pkg/notificationintent/`.
-2. Edit `go.work`:
-   - Remove `use` lines for the deleted modules.
-   - Remove `replace` lines for `galaxy/redisconn` and
-     `galaxy/notificationintent`.
-   - Do not add `./backend` yet — the module is created in Stage 2.
-3. Confirm that surviving modules still build:
-   `go build ./gateway/... ./game/... ./client/... ./pkg/...`.
-   Any compile error here means a surviving module imported a
-   removed package and must be patched (the only realistic culprit is
-   `gateway`, which references `pkg/redisconn` and the deleted streams;
-   patches there belong to Stage 6, not Stage 1 — for Stage 1 it is
-   acceptable to leave gateway broken if and only if the only failures
-   come from imports of removed packages).
-4. Run `go vet ./pkg/...` and confirm no diagnostic.
-
-Out of scope: any code change inside surviving modules. Stage 1 is
-purely deletion plus `go.work` edits.
-
-Critical files:
-
-- `go.work`
-- the deletion of `authsession/`, `lobby/`, `mail/`, `notification/`,
-  `gamemaster/`, `rtmanager/`, `geoprofile/`, `user/`, `integration/`,
-  `pkg/redisconn/`, `pkg/notificationintent/`.
-
-Done criteria:
-
-- `git status` shows only deletions plus the `go.work` edit.
-- `go build ./pkg/...` is clean.
-- `go vet ./pkg/...` is clean.
-
-## ~~Stage 2~~ — Backend skeleton & shared infrastructure
-
-This stage was implemented and marked as done.
-
-Goal: stand up the new module with its boot path, configuration,
-telemetry, logger, HTTP listener, Postgres pool, and gRPC listener — all
-with empty handlers. After this stage `go run ./backend/cmd/backend`
-must boot to a state where probes return 200 and migrations run (with an
-empty migration file).
-
-Actions:
-
-1. Create `backend/go.mod` with module path `galaxy/backend` and Go
-   version matching `go.work`. Add direct dependencies:
-   `github.com/gin-gonic/gin`, `github.com/jackc/pgx/v5`,
-   `github.com/go-jet/jet/v2`, `github.com/pressly/goose/v3`,
-   `go.uber.org/zap`, `go.opentelemetry.io/otel` and the OTLP
-   trace/metric exporters used by other services, and the `galaxy/*`
-   pkg modules (`postgres`, `model`, `geoip`, `cronutil`, `error`,
-   `util`).
-2. Add `./backend` to `go.work` `use(...)`.
-3. `backend/cmd/backend/main.go` — boot order:
-   1. Load `config.LoadFromEnv()`; `cfg.Validate()`.
-   2. Initialise telemetry (`telemetry.NewProcess(cfg.Telemetry)`). Set
-      global tracer and meter providers.
-   3. Construct the zap logger; inject trace fields helper.
-   4. Open Postgres pool. Apply embedded migrations with goose. Fail
-      fast on any error.
-   5. Construct module wiring (empty for now; populated in Stage 5).
-   6. Start the HTTP server (gin engine with empty route groups, plus
-      `/healthz` and `/readyz`).
-   7. Start the gRPC push server (no streams accepted yet — Stage 6).
-   8. Block on `signal.NotifyContext(ctx, SIGINT, SIGTERM)`; on signal,
-      drain in the order described in `README.md` §16.
-4. `backend/internal/config/config.go` — env-loader following the
-   pattern used by surviving services. Cover every variable listed in
-   `README.md` §4. Provide `DefaultConfig()` and `Validate()`.
-5. `backend/internal/telemetry/runtime.go` — port the existing service
-   pattern verbatim: configurable OTLP gRPC/HTTP exporter, optional
-   stdout exporter, Prometheus pull endpoint when configured. Expose
-   `TraceFieldsFromContext(ctx) []zap.Field`.
-6. `backend/internal/server/server.go` — gin engine, three empty route
-   groups, request id middleware, panic recovery middleware, otel
-   middleware. Probe handlers in `server/probes.go`.
-7. `backend/internal/postgres/pool.go` — pgx pool factory using the
-   shared `galaxy/postgres` helper.
-8. `backend/internal/postgres/migrations/00001_init.sql` — empty file
-   containing the `-- +goose Up` and `-- +goose Down` markers and a
-   single `CREATE SCHEMA IF NOT EXISTS backend;` statement so the
-   migration is non-empty and can be verified.
-9. `backend/internal/postgres/migrations/embed.go` — `embed.FS` and
-   exported `Migrations() fs.FS` helper.
-10. `backend/internal/push/server.go` — gRPC server skeleton bound to
-    `cfg.GRPCPushListenAddr`. No service registered yet.
-11. `backend/Makefile` — at minimum a `jet` target stub that prints
-    "not generated yet"; will be filled in Stage 4.
-
-Critical files:
-
-- `backend/go.mod`, `go.work`
-- `backend/cmd/backend/main.go`
-- `backend/internal/config/config.go`
-- `backend/internal/telemetry/runtime.go`
-- `backend/internal/server/server.go`, `backend/internal/server/probes.go`
-- `backend/internal/postgres/pool.go`,
-  `backend/internal/postgres/migrations/00001_init.sql`,
-  `backend/internal/postgres/migrations/embed.go`
-- `backend/internal/push/server.go`
-- `backend/Makefile`
-
-Done criteria:
-
-- `go build ./backend/...` is clean.
-- `go run ./backend/cmd/backend` starts, applies the placeholder
-  migration, opens HTTP and gRPC listeners, and serves `/healthz` 200
-  and `/readyz` 200.
-- Telemetry output (stdout exporter) shows trace and metric activity on
-  a probe hit.
-
-## ~~Stage~~ 3 — API contract & routing
-
-This stage was implemented and marked as done.
-
-Goal: define the entire backend REST contract in `openapi.yaml` and
-register every handler as a placeholder that returns
-`501 Not Implemented`. Wire the middleware stack for each route group.
-The contract test suite must validate every endpoint round-trip against
-the OpenAPI document and pass on the placeholders.
-
-Actions:
-
-1. Author `backend/openapi.yaml` — single document with three tags
-   (`Public`, `User`, `Admin`) and the endpoint set below. Reuse
-   schemas from `pkg/model` where possible; keep the rest under
-   `components/schemas/*`.
-2. Implement middleware in `backend/internal/server/middleware/`:
-   - `requestid` — assigns and propagates a request id (Stage 2 may
-     have already done this; consolidate here).
-   - `logging` — emits an access log entry with trace fields.
-   - `metrics` — counters and histograms per route group.
-   - `panicrecovery` — converts panics to 500 with structured logging.
-   - `userid` — required on `/api/v1/user/*`. Reads `X-User-ID`,
-     parses as UUID, places it in the request context. Rejects with
-     400 if missing or malformed. Backend trusts the value (see
-     architecture trust note).
-   - `basicauth` — required on `/api/v1/admin/*`. Stage 3 uses a stub
-     verifier that accepts any non-empty username and a fixed password
-     read from a test-only env var so contract tests can pass; Stage
-     5.3 replaces the verifier with the real Postgres-backed one.
-3. Implement handlers per endpoint in
-   `backend/internal/server/handlers_<group>_<topic>.go`. Every handler
-   returns `501 Not Implemented` with the standard error body
-   `{"error":{"code":"not_implemented","message":"..."}}`.
-4. Implement the contract test:
-   `backend/internal/server/contract_test.go`. Loads
-   `backend/openapi.yaml` via `kin-openapi`, builds the gin engine,
-   walks every operation, sends a representative request, and
-   validates both the request and response against the OpenAPI
-   document.
-5. Document `openapi.yaml` location and contract test pattern in
-   `backend/docs/api-contract.md` (a brief decision record).
-
-### Endpoint inventory
-
-Public (`/api/v1/public/*`):
-
-- `POST /auth/send-email-code` — request body `{email, locale?}`;
-  response `{challenge_id}`.
-- `POST /auth/confirm-email-code` — request body
-  `{challenge_id, code, client_public_key, time_zone}`; response
-  `{device_session_id}`.
-
-Probes (root):
-
-- `GET /healthz` — `200` always when the process is alive.
-- `GET /readyz` — `200` once Postgres reachable, migrations applied,
-  gRPC listener bound; `503` otherwise.
-
-User (`/api/v1/user/*`, all require `X-User-ID`):
-
-- `GET /account` — current account view (profile + settings +
-  entitlements).
-- `PATCH /account/profile` — update mutable profile fields
-  (`display_name`).
-- `PATCH /account/settings` — update `preferred_language`, `time_zone`.
-- `POST /account/delete` — soft delete; cascade is in process.
-
-- `GET /lobby/games` — public list with paging.
-- `POST /lobby/games` — create.
-- `GET /lobby/games/{game_id}`.
-- `PATCH /lobby/games/{game_id}`.
-- `POST /lobby/games/{game_id}/open-enrollment`.
-- `POST /lobby/games/{game_id}/ready-to-start`.
-- `POST /lobby/games/{game_id}/start`.
-- `POST /lobby/games/{game_id}/pause`.
-- `POST /lobby/games/{game_id}/resume`.
-- `POST /lobby/games/{game_id}/cancel`.
-- `POST /lobby/games/{game_id}/retry-start`.
-- `POST /lobby/games/{game_id}/applications`.
-- `POST /lobby/games/{game_id}/applications/{application_id}/approve`.
-- `POST /lobby/games/{game_id}/applications/{application_id}/reject`.
-- `POST /lobby/games/{game_id}/invites`.
-- `POST /lobby/games/{game_id}/invites/{invite_id}/redeem`.
-- `POST /lobby/games/{game_id}/invites/{invite_id}/decline`.
-- `POST /lobby/games/{game_id}/invites/{invite_id}/revoke`.
-- `GET /lobby/games/{game_id}/memberships`.
-- `POST /lobby/games/{game_id}/memberships/{membership_id}/remove`.
-- `POST /lobby/games/{game_id}/memberships/{membership_id}/block`.
-
-- `GET /lobby/my/games`.
-- `GET /lobby/my/applications`.
-- `GET /lobby/my/invites`.
-- `GET /lobby/my/race-names`.
-
-- `POST /lobby/race-names/register` — promote a `pending_registration`
-  to `registered` within the 30-day window.
-
-- `POST /games/{game_id}/commands` — proxy to engine command path.
-- `POST /games/{game_id}/orders` — proxy to engine order validation.
-- `GET /games/{game_id}/reports/{turn}` — proxy to engine report path.
-
-Admin (`/api/v1/admin/*`, all require Basic Auth):
-
-- `GET /admin-accounts`, `POST /admin-accounts`,
-  `GET /admin-accounts/{username}`,
-  `POST /admin-accounts/{username}/disable`,
-  `POST /admin-accounts/{username}/enable`,
-  `POST /admin-accounts/{username}/reset-password`.
-
-- `GET /users`, `GET /users/{user_id}`,
-  `POST /users/{user_id}/sanctions`,
-  `POST /users/{user_id}/limits`,
-  `POST /users/{user_id}/entitlements`,
-  `POST /users/{user_id}/soft-delete`.
-
-- `GET /games`, `GET /games/{game_id}`,
-  `POST /games/{game_id}/force-start`,
-  `POST /games/{game_id}/force-stop`,
-  `POST /games/{game_id}/ban-member`.
-
-- `GET /runtimes/{game_id}`,
-  `POST /runtimes/{game_id}/restart`,
-  `POST /runtimes/{game_id}/patch`,
-  `POST /runtimes/{game_id}/force-next-turn`,
-  `GET /engine-versions`, `POST /engine-versions`,
-  `PATCH /engine-versions/{id}`,
-  `POST /engine-versions/{id}/disable`.
-
-- `GET /mail/deliveries`,
-  `GET /mail/deliveries/{delivery_id}`,
-  `GET /mail/deliveries/{delivery_id}/attempts`,
-  `POST /mail/deliveries/{delivery_id}/resend`,
-  `GET /mail/dead-letters`.
-
-- `GET /notifications`, `GET /notifications/{notification_id}`,
-  `GET /notifications/dead-letters`,
-  `GET /notifications/malformed`.
-
-- `GET /geo/users/{user_id}/countries` — counter listing.
-
-Internal (gateway-only, `/api/v1/internal/*`):
-
-- `GET /sessions/{device_session_id}` — gateway session lookup.
-- `POST /sessions/{device_session_id}/revoke` — admin or self revoke
-  passthrough; backend emits `session_invalidation`.
-- `POST /sessions/users/{user_id}/revoke-all`.
-- `GET /users/{user_id}/account-internal` — server-to-server fetch
-  used by gateway flows that need account state alongside the session.
-
-The internal group is on `/api/v1/internal/*`. The trust model treats
-it as part of the user surface (no extra auth in MVP).
-
-Critical files:
-
-- `backend/openapi.yaml`
-- `backend/internal/server/router.go`
-- `backend/internal/server/middleware/{requestid,logging,metrics,panicrecovery,userid,basicauth}.go`
-- `backend/internal/server/handlers_*.go`
-- `backend/internal/server/contract_test.go`
-- `backend/docs/api-contract.md`
-
-Done criteria:
-
-- `go test ./backend/internal/server/...` is green; the contract test
-  exercises every endpoint and validates against `openapi.yaml`.
-- Every endpoint returns `501 Not Implemented` with the standard error
-  body.
-- gin route table at startup matches the OpenAPI inventory exactly.
-
-## ~~Stage 4~~ — Persistence layer
-
-This stage was implemented and marked as done.
-
-Goal: define every `backend` schema table, generate jet code, and make
-the wiring of the persistence layer ready for the domain modules.
-
-Actions:
-
-1. Replace `backend/internal/postgres/migrations/00001_init.sql` with
-   the full DDL. The schema is `backend`. The expected tables and
-   their primary purposes:
-
-   Auth:
-   - `device_sessions(device_session_id uuid pk, user_id uuid not null,
-     client_public_key bytea not null, status text not null,
-     created_at, revoked_at, last_seen_at)` plus indexes on
-     `user_id` and `status`.
-   - `auth_challenges(challenge_id uuid pk, email text not null,
-     code_hash bytea not null, created_at, expires_at, consumed_at,
-     attempts int not null default 0)`. Index on `email`.
-   - `blocked_emails(email text pk, blocked_at, reason text)`.
-
-   User:
-   - `accounts(user_id uuid pk, email text unique not null,
-     user_name text unique not null, display_name text not null,
-     preferred_language text not null, time_zone text not null,
-     declared_country text, permanent_block bool not null default false,
-     created_at, updated_at, deleted_at)`.
-   - `entitlement_records(record_id uuid pk, user_id uuid not null,
-     tier text not null, source text not null, created_at)`.
-   - `entitlement_snapshots(user_id uuid pk, tier text not null,
-     max_registered_race_names int not null, taken_at timestamptz)`.
-     Updated on every entitlement change.
-   - `sanction_records`, `sanction_active`, `limit_records`,
-     `limit_active` — same shape as the previous `user` service had
-     (record + active rollup pattern).
-
-   Admin:
-   - `admin_accounts(username text pk, password_hash bytea not null,
-     created_at, last_used_at, disabled_at)`.
-
-   Lobby:
-   - `games(game_id uuid pk, owner_user_id uuid not null,
-     visibility text not null, status text not null, ...)` covering
-     enrollment state machine fields documented in
-     `ARCHITECTURE_deprecated.md` § Game Lobby.
-   - `applications(application_id uuid pk, game_id uuid not null,
-     applicant_user_id uuid not null, status text not null, ...)`.
-   - `invites(invite_id uuid pk, game_id uuid not null,
-     invited_user_id uuid, code text unique, status text, ...)`.
-   - `memberships(membership_id uuid pk, game_id uuid not null,
-     user_id uuid not null, race_name text not null, status text,
-     ...)` plus `unique(game_id, user_id)`.
-   - `race_names(name text not null, canonical text not null,
-     status text not null, owner_user_id uuid, game_id uuid,
-     expires_at, registered_at, ...)` plus
-     `unique(canonical) where status in ('registered','reservation','pending_registration')`.
-
-   Runtime:
-   - `runtime_records(game_id uuid pk, current_container_id text,
-     status text not null, image_ref text, started_at, last_observed_at,
-     ...)`.
-   - `engine_versions(version text pk, image_ref text not null,
-     enabled bool not null default true, created_at, ...)`.
-   - `player_mappings(game_id uuid not null, user_id uuid not null,
-     race_name text not null, engine_player_uuid uuid not null,
-     primary key(game_id, user_id))`.
-   - `runtime_operation_log(operation_id uuid pk, game_id uuid,
-     op text, status text, started_at, finished_at, error text)`.
-   - `runtime_health_snapshots(snapshot_id uuid pk, game_id uuid,
-     observed_at, payload jsonb)`.
-
-   Mail:
-   - `mail_deliveries(delivery_id uuid pk, template_id text not null,
-     idempotency_key text not null, status text not null,
-     attempts int not null default 0, next_attempt_at timestamptz,
-     payload_id uuid not null, created_at, ...)` plus
-     `unique(template_id, idempotency_key)`.
-   - `mail_recipients(recipient_id uuid pk, delivery_id uuid not null,
-     address text not null, kind text not null)`.
-   - `mail_attempts(attempt_id uuid pk, delivery_id uuid, attempt_no int,
-     started_at, finished_at, outcome text, error text)`.
-   - `mail_dead_letters(dead_letter_id uuid pk, delivery_id uuid,
-     archived_at, reason text)`.
-   - `mail_payloads(payload_id uuid pk, content_type text not null,
-     subject text, body bytea not null)`.
-
-   Notification:
-   - `notifications(notification_id uuid pk, kind text not null,
-     idempotency_key text not null, user_id uuid, payload jsonb,
-     created_at)` plus `unique(kind, idempotency_key)`.
-   - `notification_routes(route_id uuid pk, notification_id uuid,
-     channel text not null, status text not null, last_attempt_at,
-     ...)`.
-   - `notification_dead_letters(dead_letter_id uuid pk, notification_id
-     uuid, archived_at, reason text)`.
-   - `notification_malformed_intents(id uuid pk, received_at, payload
-     jsonb, reason text)`.
-
-   Geo:
-   - `user_country_counters(user_id uuid not null, country text not null,
-     count bigint not null default 0, last_seen_at timestamptz,
-     primary key(user_id, country))`.
-
-2. Add `created_at TIMESTAMPTZ DEFAULT now()` to every table; add
-   `updated_at` and `deleted_at` where the domain reasons in
-   `ARCHITECTURE_deprecated.md` apply. UTC normalisation is performed
-   in Go on read and write (the existing `pkg/postgres` helpers cover
-   this).
-
-3. `backend/cmd/jetgen/main.go` — port the existing pattern from a
-   surviving reference (the previous services' `cmd/jetgen` is a good
-   template; adjust import paths to `galaxy/backend`). The tool spins
-   up a transient Postgres container, applies the embedded migrations,
-   and runs `jet -dsn=...` writing into `internal/postgres/jet/`.
-
-4. `backend/Makefile` — fill in the `jet` target.
-
-5. Run `make jet` and commit `internal/postgres/jet/`.
-
-6. Add `backend/internal/postgres/jet/jet.go` — package doc and
-   `//go:generate` comment pointing to `cmd/jetgen`.
-
-7. Sanity test in `backend/internal/postgres/migrations_test.go`:
-   spin up a Postgres testcontainer, apply migrations, assert that
-   the `backend` schema exists and that every expected table is
-   present.
-
-Critical files:
-
-- `backend/internal/postgres/migrations/00001_init.sql`
-- `backend/internal/postgres/jet/**`
-- `backend/cmd/jetgen/main.go`
-- `backend/Makefile`
-- `backend/internal/postgres/migrations_test.go`
-
-Done criteria:
-
-- `go test ./backend/internal/postgres/...` is green.
-- `make jet` regenerates without diff.
-- All tables listed above exist after a fresh migration.
-
-## ~~Stage 5~~ — Domain implementation
-
-Goal: implement domain modules in dependency order. After each substage
-the backend is functional for the substage's slice of behaviour. The
-contract tests from Stage 3 progressively flip from `501` to actual
-responses as each substage replaces placeholders.
-
-Substages run strictly in order. Each substage:
-
-- Implements package code in `backend/internal/<domain>/`.
-- Replaces the corresponding `501` handler bodies in
-  `backend/internal/server/handlers_*.go` with real logic that calls
-  the domain package.
-- Adds focused unit and contract coverage for the substage's
-  endpoints.
-- Wires the new package into `backend/cmd/backend/main.go`.
-
-### ~~5.1~~ — auth
-
-This substage was implemented and marked as done. See
-[`docs/stage05_1-auth.md`](docs/stage05_1-auth.md) for the decisions
-taken during implementation.
-
-Behaviour:
-
-- `POST /api/v1/public/auth/send-email-code` — generates a challenge,
-  hashes the code, persists in `auth_challenges`, calls
-  `mail.EnqueueLoginCode(email, code)`. Returns `{challenge_id}` for
-  every non-blocked email (existing user, new user, throttled — all
-  return identical shape; blocked email rejects with 400 only when the
-  block is permanent).
-- `POST /api/v1/public/auth/confirm-email-code` — looks up the
-  challenge, verifies the code (constant-time), enforces attempt
-  ceiling, marks consumed, calls `user.EnsureByEmail(email,
-  preferred_language, time_zone)` to obtain the user_id, stores the
-  Ed25519 public key, creates a `device_session` row, populates the
-  in-memory cache, calls
-  `geo.SetDeclaredCountryAtRegistration(user_id, source_ip)`, and
-  returns `{device_session_id}`.
-- `GET /api/v1/internal/sessions/{device_session_id}` — sync session
-  lookup for gateway.
-- `POST /api/v1/internal/sessions/{device_session_id}/revoke` and
-  `POST /api/v1/internal/sessions/users/{user_id}/revoke-all` — mark
-  sessions revoked, evict from in-memory cache, emit
-  `session_invalidation` push event (Stage 6 wires the actual
-  emission; until then `auth` calls a no-op publisher injected at
-  wiring).
-
-Cache: full session table read at startup; write-through on every
-mutation.
-
-### ~~5.2~~ — user
-
-This substage was implemented and marked as done. See
-[`docs/stage05_2-user.md`](docs/stage05_2-user.md) for the decisions
-taken during implementation.
-
-Behaviour:
-
-- Account CRUD limited to allowed mutations on profile and settings.
-- `EnsureByEmail` and `ResolveByEmail` for `auth`.
-- Entitlement records and snapshots; tier downgrades never revoke
-  already-registered race names.
-- Sanctions and limits using the record + active rollup pattern.
-- Soft delete: writes `deleted_at` and triggers in-process cascade —
-  `lobby.OnUserDeleted(user_id)`, `notification.OnUserDeleted(user_id)`,
-  `geo.OnUserDeleted(user_id)`. Permanent block triggers
-  `lobby.OnUserBlocked(user_id)`.
-- Cache: latest entitlement snapshot per user; warmed on startup;
-  write-through on entitlement mutation.
-
-### ~~5.3~~ — admin
-
-This substage was implemented and marked as done. See
-[`docs/stage05_3-admin.md`](docs/stage05_3-admin.md) for the decisions
-taken during implementation.
-
-Behaviour:
-
-- `admin_accounts` CRUD with bcrypt hashing.
-- Bootstrap on startup via env vars (`BACKEND_ADMIN_BOOTSTRAP_USER`,
-  `BACKEND_ADMIN_BOOTSTRAP_PASSWORD`); idempotent.
-- Replace the Stage 3 stub `basicauth` middleware with the real
-  Postgres-backed verifier. Constant-time comparison via bcrypt.
-- Admin CRUD endpoints across users, games, runtime, mail,
-  notification, geo. Each admin endpoint delegates to the domain
-  package's admin-facing methods.
-
-Cache: full admin table at startup; write-through on mutation.
-
-### ~~5.4~~ — lobby
-
-This substage was implemented and marked as done. See
-[`docs/stage05_4-lobby.md`](docs/stage05_4-lobby.md) for the decisions
-taken during implementation.
-
-Behaviour:
-
-- Games CRUD with the enrollment state machine.
-- Applications and invites with their lifecycles.
-- Memberships with race name binding.
-- Race Name Directory: registered, reservation, and
-  pending_registration tiers; canonical key via `disciplinedware/go-confusables`;
-  uniqueness across all three tiers; capability promotion based on
-  `max_planets > initial AND max_population > initial` from the
-  runtime snapshot.
-- Pending-registration sweeper: scheduled job, releases entries past
-  the 30-day window; uses `pkg/cronutil`. The same sweeper auto-closes
-  enrollment-expired games whose `approved_count >= min_players`.
-- Hooks consumed from other modules:
-  - `OnUserBlocked(user_id)` — release all RND/applications/invites/
-    memberships in one transaction.
-  - `OnUserDeleted(user_id)` — same.
-  - `OnRuntimeSnapshot(snapshot)` — update denormalised runtime view
-    on the game (current_turn, status, per-member max stats).
-  - `OnGameFinished(game_id)` — drive race name promotion logic and
-    move game to `finished`.
-
-Cache: active games and memberships, RND canonical set; warmed on
-startup; write-through on mutation.
-
-### ~~5.5~~ — runtime (with dockerclient and engineclient)
-
-This substage was implemented and marked as done. See
-[`docs/stage05_5-runtime.md`](docs/stage05_5-runtime.md) for the
-decisions taken during implementation.
-
-Behaviour:
-
-- Engine version registry CRUD.
-- `engineclient` is a thin `net/http` client over `pkg/model` types,
-  one method per engine endpoint listed in `README.md` §8.
-- `dockerclient` wraps `github.com/docker/docker` for: pull, create,
-  start, stop, remove, inspect, list (filtered by the
-  `galaxy.backend=1` label), patch (semver-only, validated against
-  `engine_versions`).
-- Per-game serialisation: a `sync.Map[game_id]*sync.Mutex` ensures
-  concurrent ops on the same game are sequential.
-- Worker pool for long-running operations: started in Stage 5.5; jobs
-  enqueued on a buffered channel; bounded concurrency.
-- `runtime_operation_log` records every op (start time, finish time,
-  outcome, error).
-- Reconciliation: on startup and on a `pkg/cronutil` schedule, list
-  containers labelled `galaxy.backend=1`, match against
-  `runtime_records`, adopt unrecorded labelled containers, mark
-  recorded but missing as removed. Emit
-  `lobby.OnRuntimeJobResult` for each removed.
-- Snapshot publication: after every successful engine read or a
-  health-probe transition, synthesise a snapshot and call
-  `lobby.OnRuntimeSnapshot(snapshot)` synchronously.
-- Turn scheduler: `pkg/cronutil` schedule per running game; each tick
-  invokes the engine `admin/turn`, on success snapshots and publishes;
-  force-next-turn sets a one-shot skip flag stored in
-  `runtime_records`.
-
-Cache: active runtime records, engine version registry; warmed on
-startup; write-through on mutation.
-
-### ~~5.6~~ — mail
-
-This substage was implemented and marked as done. See
-[`docs/stage05_6-mail.md`](docs/stage05_6-mail.md) for the decisions
-taken during implementation.
-
-Behaviour:
-
-- Outbox tables defined in Stage 4.
-- Worker goroutine: scans `mail_deliveries` with
-  `SELECT ... FOR UPDATE SKIP LOCKED` ordered by `next_attempt_at`,
-  attempts SMTP delivery via `wneessen/go-mail`, records in
-  `mail_attempts`, updates status, schedules backoff with jitter, or
-  dead-letters past the configured maximum attempts.
-- Drain on startup: replays all `pending` and `retrying` rows.
-- Public API for producers: `EnqueueLoginCode(email, code, ttl)`,
-  `EnqueueTemplate(template_id, recipient, payload, idempotency_key)`.
-- Admin endpoints implemented: list, view, resend.
-
-### ~~5.7~~ — notification
-
-This substage was implemented and marked as done. See
-[`docs/stage05_7-notification.md`](docs/stage05_7-notification.md) for
-the decisions taken during implementation.
-
-Behaviour:
-
-- `Submit(intent)` — validate intent shape, enforce idempotency,
-  persist `notifications`, materialise `notification_routes`, fan out
-  to push (Stage 6 wires the actual push emission; until then a no-op
-  publisher) and email (`mail.EnqueueTemplate`).
-- Each kind has a fixed channel set documented in `README.md` §10.
-- Malformed intents go to `notification_malformed_intents` and never
-  block the producer.
-- Dead-letter handling: a failed route past max attempts moves to
-  `notification_dead_letters`.
-- Producers (lobby, runtime, geo, auth) are wired via direct function
-  calls.
-
-### ~~5.8~~ — geo
-
-This substage was implemented and marked as done. See
-[`docs/stage05_8-geo.md`](docs/stage05_8-geo.md) for the decisions
-taken during implementation.
-
-Behaviour:
-
-- Load GeoLite2 Country DB at startup from `BACKEND_GEOIP_DB_PATH`.
-- `SetDeclaredCountryAtRegistration(user_id, ip)` — sync; lookup,
-  update `accounts.declared_country`. No-op on lookup error.
-- `IncrementCounterAsync(user_id, ip)` — fire-and-forget goroutine;
-  upsert `user_country_counters` with `count = count + 1`,
-  `last_seen_at = now()`.
-- Middleware on `/api/v1/user/*` extracts the source IP from
-  `X-Forwarded-For` (or `RemoteAddr`) and calls
-  `IncrementCounterAsync` after the handler returns successfully.
-- `OnUserDeleted(user_id)` — delete the user's counter rows.
-
-Critical files (Stage 5 as a whole):
-
-- `backend/internal/auth/**`
-- `backend/internal/user/**`
-- `backend/internal/admin/**`
-- `backend/internal/lobby/**`
-- `backend/internal/runtime/**`
-- `backend/internal/dockerclient/**`
-- `backend/internal/engineclient/**`
-- `backend/internal/mail/**`
-- `backend/internal/notification/**`
-- `backend/internal/geo/**`
-- `backend/internal/server/handlers_*.go` (replacing 501 stubs)
-- `backend/cmd/backend/main.go` (wiring expansion)
-
-Done criteria:
-
-- All Stage 3 contract tests pass against real responses.
-- Each substage adds focused unit tests (`testify`, mocks where
-  external boundaries justify them).
-- `go run ./backend/cmd/backend` boots, all caches warm, all workers
-  start.
-
-## ~~Stage 6~~ — Push gRPC interface and gateway adaptation
-
-Goal: stand up the bidirectional control channel between backend and
-gateway. Backend pushes `client_event` and `session_invalidation`;
-gateway opens the stream, signs and forwards client events, immediately
-acts on session invalidations. Remove every Redis dependency from
-gateway except anti-replay reservations.
-
-### ~~6.1~~ — Backend push server
-
-This substage was implemented and marked as done. See
-[`docs/stage06_1-push.md`](docs/stage06_1-push.md) for the decisions
-taken during implementation.
-
-Actions:
-
-1. Author `backend/proto/push/v1/push.proto` with
-   `service Push { rpc SubscribePush(GatewaySubscribeRequest) returns
-   (stream PushEvent); }` and the message types defined in
-   `README.md` §7. Include a `cursor` field (string).
-2. `backend/buf.yaml`, `backend/buf.gen.yaml` mirroring the gateway
-   pattern; generate Go bindings into `backend/proto/push/v1/`.
-3. `backend/internal/push/server.go` — gRPC service implementation:
-   - Maintains a connection registry keyed by gateway client id (the
-     `GatewaySubscribeRequest` provides one; if multiple gateway
-     instances connect, each gets its own queue).
-   - Holds an in-memory ring buffer keyed by cursor, with TTL equal to
-     `BACKEND_FRESHNESS_WINDOW`. Cursors past TTL are discarded.
-   - Resume: if the client's cursor is still in the buffer, replay
-     from there; otherwise replay nothing and start fresh.
-   - Backpressure: per-connection buffered channel; on overflow, drop
-     the oldest events for that connection and log.
-4. Provide a publisher API consumed by `auth`, `lobby`, `notification`,
-   and `runtime`:
-   - `push.PublishClientEvent(user_id, device_session_id?, payload, kind)`.
-   - `push.PublishSessionInvalidation(device_session_id|user_id, reason)`.
-
-### ~~6.2~~ — Gateway adaptation
-
-This substage was implemented and marked as done. See
-[`docs/stage06_2-gateway.md`](docs/stage06_2-gateway.md) for the
-decisions taken during implementation.
-
-Actions:
-
-1. Remove `redisconn` usage for session projection and for the two
-   stream consumers. Keep `redisconn` only for anti-replay
-   reservations.
-2. Remove `gateway/internal/config` env vars
-   `GATEWAY_SESSION_EVENTS_REDIS_STREAM` and
-   `GATEWAY_CLIENT_EVENTS_REDIS_STREAM`. Add
-   `GATEWAY_BACKEND_HTTP_URL` and `GATEWAY_BACKEND_GRPC_PUSH_URL`.
-3. Add `gateway/internal/backendclient/` with:
-   - `RESTClient` — HTTP client for `/api/v1/internal/sessions/...` and
-     for forwarding public/user requests.
-   - `PushClient` — gRPC client to `SubscribePush` with reconnect
-     loop, exponential backoff with jitter, and cursor persistence in
-     process memory.
-4. Replace gateway session validation with a sync REST call to
-   backend per request.
-5. Replace gateway client-events Redis consumer with the
-   `SubscribePush` consumer. On `client_event`: sign envelope (Ed25519)
-   and deliver to the matching client subscription. On
-   `session_invalidation`: look up active subscriptions for the target
-   sessions, close them, and reject any in-flight authenticated
-   request bound to those sessions.
-6. Anti-replay request_id reservations remain in Redis (unchanged).
-7. Update gateway tests to use a mocked backend HTTP and gRPC server.
-
-Critical files:
-
-- `backend/proto/push/v1/push.proto`
-- `backend/buf.yaml`, `backend/buf.gen.yaml`
-- `backend/internal/push/server.go`,
-  `backend/internal/push/publisher.go`
-- `gateway/internal/backendclient/*.go`
-- `gateway/internal/config/config.go` (env var changes)
-- `gateway/internal/handlers/*.go` (route forwarding to backend)
-- `gateway/internal/auth/*.go` (session lookup → REST)
-- `gateway/internal/eventfanout/*.go` (replace Redis consumer with
-  gRPC consumer; rename if helpful)
-
-Done criteria:
-
-- `go run ./backend/cmd/backend` and `go run ./gateway/cmd/gateway`
-  cooperate end-to-end with no Redis stream usage.
-- A revocation through the admin surface causes immediate stream
-  closure on the affected client.
-- Gateway anti-replay still rejects duplicates.
-- gateway test suite green.
-
-## ~~Stage 7~~ — Integration testing
-
-This stage was implemented and marked as done. See
-[`docs/stage07-integration.md`](docs/stage07-integration.md) for the
-decisions taken during implementation, including the testenv layout,
-the signed-envelope gRPC client, and the per-scenario coverage notes.
-
-Goal: end-to-end coverage of the platform with real binaries and real
-infrastructure where practical.
-
-Actions:
-
-1. Recreate the top-level `integration/` module, registered in
-   `go.work`. The module hosts black-box test suites that drive
-   `gateway` from outside and verify behaviour at the public boundary
-   (with `backend` and `game` running in containers).
-2. Add testcontainers fixtures: Postgres, an SMTP capture server (for
-   example `axllent/mailpit`), the `galaxy/game` engine image, the
-   `galaxy/backend` image (built from this repo), and the
-   `galaxy/gateway` image. The Docker daemon used by testcontainers
-   is the same one backend will use to manage engines.
-3. Add a synthetic GeoLite2 mmdb (use `pkg/geoip/test-data/`).
-4. Cover scenarios:
-   - Registration flow: send-email-code → confirm-email-code →
-     `declared_country` populated from synthetic mmdb.
-   - User account fetch: `X-User-ID` path returns the expected
-     account; geo counter increments per request.
-   - Lobby flow: create game → invite → application → ready-to-start
-     → start (engine container starts, healthz green, status read) →
-     command → force-next-turn → finish → race name promotion.
-   - Mail flow: trigger an email-bound notification → SMTP capture
-     receives it → admin resend works.
-   - Notification flow: lobby invite triggers a push event reaching
-     the test client's gateway subscription, plus an email captured
-     by SMTP.
-   - Admin flow: bootstrap admin authenticates; CRUD admin creates a
-     second admin; second admin disables the first.
-   - Soft delete flow: user soft-delete cascades; their RND entries,
-     memberships, applications, invites, geo counters are released
-     or removed.
-   - Session revocation: admin revokes a session → push
-     `session_invalidation` arrives at gateway → active subscription
-     closes; subsequent requests with that `device_session_id`
-     rejected by gateway.
-   - Anti-replay: same `request_id` replayed within freshness window
-     is rejected by gateway.
-5. CI: run `go test ./integration/... -tags=integration` (or whichever
-   flag the team prefers). Tests requiring real Docker run only when
-   a Docker daemon is available; otherwise they skip with a clear
-   message.
-
-Critical files:
-
-- `integration/go.mod`
-- `integration/auth_flow_test.go`
-- `integration/lobby_flow_test.go`
-- `integration/mail_flow_test.go`
-- `integration/notification_flow_test.go`
-- `integration/admin_flow_test.go`
-- `integration/soft_delete_test.go`
-- `integration/session_revoke_test.go`
-- `integration/anti_replay_test.go`
-- `integration/testenv/*.go` (shared fixtures)
-
-Done criteria:
-
-- `go test ./integration/...` runs the full suite.
-- All listed scenarios pass green on a developer machine with Docker
-  available.
-- Failures produce actionable diagnostics (logs from each component
-  attached to the test report).
-
-## Stage acceptance and decision records
-
-After each stage, the implementing engineer writes a short decision
-record under `backend/docs/stage<NN>-<topic>.md` capturing any
-non-trivial choice made during implementation that is not obvious from
-the code or from this plan. Records that contradict this plan must be
-brought to the architecture conversation before merge — the plan and
-the architecture document are the agreed contract.

backend/README.md

@@ -45,6 +45,7 @@ backend/
 │   ├── admin/           # admin_accounts, Basic Auth verifier, admin operations
 │   ├── auth/            # email-code challenges, device sessions, Ed25519 keys
 │   ├── config/          # env-var loader, Validate
+│   ├── diplomail/       # diplomatic-mail messages, recipients, translations
 │   ├── dockerclient/    # docker/docker wrapper for container ops
 │   ├── engineclient/    # net/http client to galaxy-game containers
 │   ├── geo/             # geoip lookup, declared_country, per-user counters
@@ -131,6 +132,12 @@ fast.
 | `BACKEND_NOTIFICATION_ADMIN_EMAIL`      | no       | —                             | Recipient address for admin-channel notifications (`runtime.*` kinds). When empty, admin-channel routes are recorded as `skipped` and the catalog is partially silenced. |
 | `BACKEND_NOTIFICATION_WORKER_INTERVAL`  | no       | `5s`                          | Notification route worker scan interval. |
 | `BACKEND_NOTIFICATION_MAX_ATTEMPTS`     | no       | `8`                           | Notification route delivery attempts before dead-lettering. |
+| `BACKEND_DIPLOMAIL_MAX_BODY_BYTES`      | no       | `4096`                        | Maximum size of `diplomail_messages.body` enforced at send time. Tune at runtime without a migration. |
+| `BACKEND_DIPLOMAIL_MAX_SUBJECT_BYTES`   | no       | `256`                         | Maximum size of `diplomail_messages.subject`. Subject is optional; empty is always accepted. |
+| `BACKEND_DIPLOMAIL_TRANSLATOR_URL`      | no       | —                             | Base URL of a LibreTranslate-compatible instance (`http://libretranslate:5000`). Empty → translator falls through to no-op (recipients are delivered with the original body). |
+| `BACKEND_DIPLOMAIL_TRANSLATOR_TIMEOUT`  | no       | `10s`                         | Per-request HTTP timeout for the translation worker. |
+| `BACKEND_DIPLOMAIL_TRANSLATOR_MAX_ATTEMPTS` | no   | `5`                           | Number of failed HTTP attempts before the worker delivers the message with the original body (fallback). |
+| `BACKEND_DIPLOMAIL_WORKER_INTERVAL`     | no       | `2s`                          | How often the async translation worker scans for pending pairs. The worker processes one pair per tick. |
 
 If `BACKEND_ADMIN_BOOTSTRAP_USER` is set without
 `BACKEND_ADMIN_BOOTSTRAP_PASSWORD`, `Validate()` fails. If neither is
@@ -333,15 +340,42 @@ cannot guarantee.
 | `runtime.image_pull_failed`         | admin email   | `game_id`, `image_ref`                                   |
 | `runtime.container_start_failed`    | admin email   | `game_id`                                                |
 | `runtime.start_config_invalid`      | admin email   | `game_id`, `reason`                                      |
+| `game.turn.ready`                   | push          | `game_id`, `turn`                                        |
+| `game.paused`                       | push          | `game_id`, `turn`, `reason`                              |
 
 Admin-channel kinds (`runtime.*`) deliver email to
 `BACKEND_NOTIFICATION_ADMIN_EMAIL`; when the variable is empty, those
 routes land in `notification_routes` with `status='skipped'` and the
 operator log line records the configuration miss.
 
-`game.*` (`game.started`, `game.turn.ready`, `game.generation.failed`,
+`game.turn.ready` and `game.paused` are emitted by
-`game.finished`) and `mail.dead_lettered` are reserved kinds without a
+`lobby.Service.OnRuntimeSnapshot`
-producer in the catalog; adding them is an additive change to the
+(`backend/internal/lobby/runtime_hooks.go`):
+
+- `game.turn.ready` fires whenever the engine's `current_turn`
+  advances. Idempotency key `turn-ready:<game_id>:<turn>`, JSON
+  payload `{game_id, turn}`.
+- `game.paused` fires whenever the same hook flips the game
+  `running → paused` because a runtime snapshot landed with
+  `engine_unreachable` / `generation_failed`. Idempotency key
+  `paused:<game_id>:<turn>`, JSON payload
+  `{game_id, turn, reason}` (reason carries the runtime status
+  that triggered the transition). The runtime scheduler
+  (`backend/internal/runtime/scheduler.go`) forwards the failing
+  snapshot through `Service.publishFailureSnapshot` so a single
+  failing tick reliably reaches lobby.
+
+Both kinds target every active membership and route through the
+push channel only — per-turn / per-pause email would be spam — so
+the UI's signed `SubscribeEvents` stream
+(`ui/frontend/src/api/events.svelte.ts`) is the sole delivery
+path. The order tab consumes them via
+`OrderDraftStore.resetForNewTurn` / `markPaused`
+(`ui/docs/sync-protocol.md`).
+
+The remaining `game.*` (`game.started`, `game.generation.failed`,
+`game.finished`) and `mail.dead_lettered` are reserved kinds without
+a producer in the catalog; adding them is an additive change to the
 catalog vocabulary and the migration CHECK constraint.
 
 Templates ship in English only; localisation belongs to clients that

backend/cmd/backend/main.go

@@ -12,11 +12,23 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
+	"time"
+
+	// time/tzdata embeds the IANA timezone database so time.LoadLocation
+	// works in container images without /usr/share/zoneinfo (distroless
+	// static, alpine without the tzdata apk). The auth and user-settings
+	// flows validate the caller's `time_zone` via time.LoadLocation;
+	// without this import only "UTC" and fixed offsets would resolve.
+	_ "time/tzdata"
 
 	"galaxy/backend/internal/admin"
 	"galaxy/backend/internal/app"
 	"galaxy/backend/internal/auth"
 	"galaxy/backend/internal/config"
+	"galaxy/backend/internal/devsandbox"
+	"galaxy/backend/internal/diplomail"
+	"galaxy/backend/internal/diplomail/detector"
+	"galaxy/backend/internal/diplomail/translator"
 	"galaxy/backend/internal/dockerclient"
 	"galaxy/backend/internal/engineclient"
 	"galaxy/backend/internal/geo"
@@ -123,6 +135,7 @@ func run(ctx context.Context) (err error) {
 	lobbyCascade := &lobbyCascadeAdapter{}
 	userNotifyCascade := &userNotificationCascadeAdapter{}
 	lobbyNotifyPublisher := &lobbyNotificationPublisherAdapter{}
+	lobbyDiplomailPublisher := &lobbyDiplomailPublisherAdapter{}
 	runtimeNotifyPublisher := &runtimeNotificationPublisherAdapter{}
 
 	userSvc := user.NewService(user.Deps{
@@ -189,6 +202,7 @@ func run(ctx context.Context) (err error) {
 		Cache:        lobbyCache,
 		Runtime:      runtimeGateway,
 		Notification: lobbyNotifyPublisher,
+		Diplomail:    lobbyDiplomailPublisher,
 		Entitlement:  &userEntitlementAdapter{svc: userSvc},
 		Config:       cfg.Lobby,
 		Logger:       logger,
@@ -258,6 +272,29 @@ func run(ctx context.Context) (err error) {
 	)
 	runtimeGateway.svc = runtimeSvc
 
+	// Run a single reconciliation pass before the dev-sandbox
+	// bootstrap so any runtime row pointing at a vanished engine
+	// container (host reboot wiped /tmp/galaxy-game-state/<uuid>;
+	// `tools/local-dev`'s `prune-broken-engines` target reaped the
+	// husk) is already cascaded through `markRemoved` → lobby
+	// `cancelled` by the time the bootstrap walks the sandbox list.
+	// Without this pre-tick the bootstrap would reuse the
+	// soon-to-be-cancelled game and force the developer into a
+	// second `make up` cycle to land a healthy sandbox. Failures are
+	// non-fatal: the periodic ticker started later catches up, and
+	// the worst case degrades to the legacy two-cycle recovery.
+	if err := runtimeSvc.Reconciler().Tick(ctx); err != nil {
+		logger.Warn("pre-bootstrap reconciler tick failed", zap.Error(err))
+	}
+
+	if err := devsandbox.Bootstrap(ctx, devsandbox.Deps{
+		Users:          userSvc,
+		Lobby:          lobbySvc,
+		EngineVersions: engineVersionSvc,
+	}, cfg.DevSandbox, logger); err != nil {
+		return fmt.Errorf("dev sandbox bootstrap: %w", err)
+	}
+
 	notifStore := notification.NewStore(db)
 	notifSvc := notification.NewService(notification.Deps{
 		Store:    notifStore,
@@ -270,6 +307,25 @@ func run(ctx context.Context) (err error) {
 	userNotifyCascade.svc = notifSvc
 	lobbyNotifyPublisher.svc = notifSvc
 	runtimeNotifyPublisher.svc = notifSvc
+
+	diplomailStore := diplomail.NewStore(db)
+	diplomailTranslator, err := buildDiplomailTranslator(cfg.Diplomail, logger)
+	if err != nil {
+		return fmt.Errorf("build diplomail translator: %w", err)
+	}
+	diplomailSvc := diplomail.NewService(diplomail.Deps{
+		Store:        diplomailStore,
+		Memberships:  &diplomailMembershipAdapter{lobby: lobbySvc, users: userSvc},
+		Notification: &diplomailNotificationPublisherAdapter{svc: notifSvc},
+		Entitlements: &diplomailEntitlementAdapter{users: userSvc},
+		Games:        &diplomailGameAdapter{lobby: lobbySvc},
+		Detector:     detector.New(),
+		Translator:   diplomailTranslator,
+		Config:       cfg.Diplomail,
+		Logger:       logger,
+	})
+	lobbyDiplomailPublisher.svc = diplomailSvc
+	diplomailWorker := diplomail.NewWorker(diplomailSvc)
 	if email := cfg.Notification.AdminEmail; email == "" {
 		logger.Info("notification admin email not configured (BACKEND_NOTIFICATION_ADMIN_EMAIL); admin-channel routes will be skipped")
 	} else {
@@ -294,9 +350,11 @@ func run(ctx context.Context) (err error) {
 	adminEngineVersionsHandlers := backendserver.NewAdminEngineVersionsHandlers(engineVersionSvc, logger)
 	adminRuntimesHandlers := backendserver.NewAdminRuntimesHandlers(runtimeSvc, logger)
 	adminMailHandlers := backendserver.NewAdminMailHandlers(mailSvc, logger)
+	adminDiplomailHandlers := backendserver.NewAdminDiplomailHandlers(diplomailSvc, logger)
 	adminNotificationsHandlers := backendserver.NewAdminNotificationsHandlers(notifSvc, logger)
 	adminGeoHandlers := backendserver.NewAdminGeoHandlers(geoSvc, logger)
 	userGamesHandlers := backendserver.NewUserGamesHandlers(runtimeSvc, engineCli, logger)
+	userMailHandlers := backendserver.NewUserMailHandlers(diplomailSvc, lobbySvc, userSvc, logger)
 
 	ready := func() bool {
 		return authCache.Ready() && userCache.Ready() && adminCache.Ready() && lobbyCache.Ready() && runtimeCache.Ready()
@@ -325,9 +383,11 @@ func run(ctx context.Context) (err error) {
 		AdminRuntimes:         adminRuntimesHandlers,
 		AdminEngineVersions:   adminEngineVersionsHandlers,
 		AdminMail:             adminMailHandlers,
+		AdminDiplomail:        adminDiplomailHandlers,
 		AdminNotifications:    adminNotificationsHandlers,
 		AdminGeo:              adminGeoHandlers,
 		UserGames:             userGamesHandlers,
+		UserMail:              userMailHandlers,
 	})
 	if err != nil {
 		return fmt.Errorf("build backend router: %w", err)
@@ -343,7 +403,7 @@ func run(ctx context.Context) (err error) {
 	runtimeScheduler := runtimeSvc.SchedulerComponent()
 	runtimeReconciler := runtimeSvc.Reconciler()
 
-	components := []app.Component{httpServer, pushServer, mailWorker, notifWorker, lobbySweeper, runtimeWorkers, runtimeScheduler, runtimeReconciler}
+	components := []app.Component{httpServer, pushServer, mailWorker, notifWorker, diplomailWorker, lobbySweeper, runtimeWorkers, runtimeScheduler, runtimeReconciler}
 	if metricsServer.Enabled() {
 		components = append(components, metricsServer)
 	}
@@ -548,3 +608,288 @@ func (a *runtimeNotificationPublisherAdapter) PublishRuntimeEvent(ctx context.Co
 	}
 	return a.svc.RuntimeAdapter().PublishRuntimeEvent(ctx, kind, idempotencyKey, payload)
 }
+
+// diplomailMembershipAdapter implements `diplomail.MembershipLookup`
+// by walking the lobby cache (for active rows) and the lobby service
+// (for any-status rows) and stitching each membership row to the
+// immutable `accounts.user_name` resolved through `*user.Service`.
+type diplomailMembershipAdapter struct {
+	lobby *lobby.Service
+	users *user.Service
+}
+
+func (a *diplomailMembershipAdapter) GetActiveMembership(ctx context.Context, gameID, userID uuid.UUID) (diplomail.ActiveMembership, error) {
+	if a == nil || a.lobby == nil || a.users == nil {
+		return diplomail.ActiveMembership{}, diplomail.ErrNotFound
+	}
+	cache := a.lobby.Cache()
+	if cache == nil {
+		return diplomail.ActiveMembership{}, diplomail.ErrNotFound
+	}
+	game, ok := cache.GetGame(gameID)
+	if !ok {
+		return diplomail.ActiveMembership{}, diplomail.ErrNotFound
+	}
+	var found *lobby.Membership
+	for _, m := range cache.MembershipsForGame(gameID) {
+		if m.UserID == userID {
+			mm := m
+			found = &mm
+			break
+		}
+	}
+	if found == nil {
+		return diplomail.ActiveMembership{}, diplomail.ErrNotFound
+	}
+	account, err := a.users.GetAccount(ctx, userID)
+	if err != nil {
+		return diplomail.ActiveMembership{}, err
+	}
+	return diplomail.ActiveMembership{
+		UserID:            userID,
+		GameID:            gameID,
+		GameName:          game.GameName,
+		UserName:          account.UserName,
+		RaceName:          found.RaceName,
+		PreferredLanguage: account.PreferredLanguage,
+	}, nil
+}
+
+func (a *diplomailMembershipAdapter) GetMembershipAnyStatus(ctx context.Context, gameID, userID uuid.UUID) (diplomail.MemberSnapshot, error) {
+	if a == nil || a.lobby == nil || a.users == nil {
+		return diplomail.MemberSnapshot{}, diplomail.ErrNotFound
+	}
+	game, ok := a.lobby.Cache().GetGame(gameID)
+	if !ok {
+		return diplomail.MemberSnapshot{}, diplomail.ErrNotFound
+	}
+	members, err := a.lobby.ListMembershipsForGame(ctx, gameID)
+	if err != nil {
+		return diplomail.MemberSnapshot{}, err
+	}
+	var found *lobby.Membership
+	for _, m := range members {
+		if m.UserID == userID {
+			mm := m
+			found = &mm
+			break
+		}
+	}
+	if found == nil {
+		return diplomail.MemberSnapshot{}, diplomail.ErrNotFound
+	}
+	account, err := a.users.GetAccount(ctx, userID)
+	if err != nil {
+		return diplomail.MemberSnapshot{}, err
+	}
+	return diplomail.MemberSnapshot{
+		UserID:            userID,
+		GameID:            gameID,
+		GameName:          game.GameName,
+		UserName:          account.UserName,
+		RaceName:          found.RaceName,
+		Status:            found.Status,
+		PreferredLanguage: account.PreferredLanguage,
+	}, nil
+}
+
+func (a *diplomailMembershipAdapter) ListMembers(ctx context.Context, gameID uuid.UUID, scope string) ([]diplomail.MemberSnapshot, error) {
+	if a == nil || a.lobby == nil || a.users == nil {
+		return nil, diplomail.ErrNotFound
+	}
+	game, ok := a.lobby.Cache().GetGame(gameID)
+	if !ok {
+		return nil, diplomail.ErrNotFound
+	}
+	members, err := a.lobby.ListMembershipsForGame(ctx, gameID)
+	if err != nil {
+		return nil, err
+	}
+	matches := func(status string) bool {
+		switch scope {
+		case diplomail.RecipientScopeActive:
+			return status == lobby.MembershipStatusActive
+		case diplomail.RecipientScopeActiveAndRemoved:
+			return status == lobby.MembershipStatusActive || status == lobby.MembershipStatusRemoved
+		case diplomail.RecipientScopeAllMembers:
+			return true
+		default:
+			return status == lobby.MembershipStatusActive
+		}
+	}
+	out := make([]diplomail.MemberSnapshot, 0, len(members))
+	for _, m := range members {
+		if !matches(m.Status) {
+			continue
+		}
+		account, err := a.users.GetAccount(ctx, m.UserID)
+		if err != nil {
+			return nil, fmt.Errorf("resolve user_name for %s: %w", m.UserID, err)
+		}
+		out = append(out, diplomail.MemberSnapshot{
+			UserID:            m.UserID,
+			GameID:            gameID,
+			GameName:          game.GameName,
+			UserName:          account.UserName,
+			RaceName:          m.RaceName,
+			Status:            m.Status,
+			PreferredLanguage: account.PreferredLanguage,
+		})
+	}
+	return out, nil
+}
+
+// lobbyDiplomailPublisherAdapter implements `lobby.DiplomailPublisher`
+// by translating each lobby.LifecycleEvent into the diplomail
+// vocabulary and delegating to `*diplomail.Service.PublishLifecycle`.
+// The svc pointer is patched once diplomailSvc exists — diplomail
+// depends on lobby through MembershipLookup, so the lobby service
+// is constructed first and patched up.
+type lobbyDiplomailPublisherAdapter struct {
+	svc *diplomail.Service
+}
+
+func (a *lobbyDiplomailPublisherAdapter) PublishLifecycle(ctx context.Context, ev lobby.LifecycleEvent) error {
+	if a == nil || a.svc == nil {
+		return nil
+	}
+	return a.svc.PublishLifecycle(ctx, diplomail.LifecycleEvent{
+		GameID:     ev.GameID,
+		Kind:       ev.Kind,
+		Actor:      ev.Actor,
+		Reason:     ev.Reason,
+		TargetUser: ev.TargetUser,
+	})
+}
+
+// buildDiplomailTranslator selects the diplomail translator backend
+// from configuration: a non-empty `TranslatorURL` constructs the
+// LibreTranslate HTTP client; an empty URL falls through to the
+// noop translator so deployments without a translation service still
+// boot and deliver mail with the fallback path.
+func buildDiplomailTranslator(cfg config.DiplomailConfig, logger *zap.Logger) (translator.Translator, error) {
+	if cfg.TranslatorURL == "" {
+		logger.Info("diplomail translator URL not configured, using noop translator")
+		return translator.NewNoop(), nil
+	}
+	return translator.NewLibreTranslate(translator.LibreTranslateConfig{
+		URL:     cfg.TranslatorURL,
+		Timeout: cfg.TranslatorTimeout,
+	})
+}
+
+// diplomailEntitlementAdapter implements
+// `diplomail.EntitlementReader` by reading the user-service
+// entitlement snapshot. The IsPaid flag mirrors the per-tier policy
+// defined in `internal/user`, so updates to the tier set (monthly,
+// yearly, permanent, …) flow through without changes here.
+type diplomailEntitlementAdapter struct {
+	users *user.Service
+}
+
+func (a *diplomailEntitlementAdapter) IsPaidTier(ctx context.Context, userID uuid.UUID) (bool, error) {
+	if a == nil || a.users == nil {
+		return false, nil
+	}
+	snap, err := a.users.GetEntitlementSnapshot(ctx, userID)
+	if err != nil {
+		return false, err
+	}
+	return snap.IsPaid, nil
+}
+
+// diplomailGameAdapter implements `diplomail.GameLookup`. The
+// running-games and finished-games queries walk the lobby cache so
+// the admin multi-game broadcast and bulk-purge endpoints do not
+// fan out a per-game DB query each time. GetGame falls back to the
+// cache; an unknown id is surfaced as ErrNotFound (the diplomail
+// sentinel).
+type diplomailGameAdapter struct {
+	lobby *lobby.Service
+}
+
+func (a *diplomailGameAdapter) ListRunningGames(_ context.Context) ([]diplomail.GameSnapshot, error) {
+	if a == nil || a.lobby == nil || a.lobby.Cache() == nil {
+		return nil, nil
+	}
+	var out []diplomail.GameSnapshot
+	for _, game := range a.lobby.Cache().ListGames() {
+		if !isRunningStatus(game.Status) {
+			continue
+		}
+		out = append(out, gameSnapshot(game))
+	}
+	return out, nil
+}
+
+func (a *diplomailGameAdapter) ListFinishedGamesBefore(ctx context.Context, cutoff time.Time) ([]diplomail.GameSnapshot, error) {
+	if a == nil || a.lobby == nil {
+		return nil, nil
+	}
+	games, err := a.lobby.ListFinishedGamesBefore(ctx, cutoff)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]diplomail.GameSnapshot, 0, len(games))
+	for _, g := range games {
+		out = append(out, gameSnapshot(g))
+	}
+	return out, nil
+}
+
+func (a *diplomailGameAdapter) GetGame(_ context.Context, gameID uuid.UUID) (diplomail.GameSnapshot, error) {
+	if a == nil || a.lobby == nil || a.lobby.Cache() == nil {
+		return diplomail.GameSnapshot{}, diplomail.ErrNotFound
+	}
+	game, ok := a.lobby.Cache().GetGame(gameID)
+	if !ok {
+		return diplomail.GameSnapshot{}, diplomail.ErrNotFound
+	}
+	return gameSnapshot(game), nil
+}
+
+func gameSnapshot(g lobby.GameRecord) diplomail.GameSnapshot {
+	out := diplomail.GameSnapshot{
+		GameID:   g.GameID,
+		GameName: g.GameName,
+		Status:   g.Status,
+	}
+	if g.FinishedAt != nil {
+		f := *g.FinishedAt
+		out.FinishedAt = &f
+	}
+	return out
+}
+
+func isRunningStatus(status string) bool {
+	switch status {
+	case lobby.GameStatusReadyToStart, lobby.GameStatusStarting, lobby.GameStatusRunning, lobby.GameStatusPaused:
+		return true
+	default:
+		return false
+	}
+}
+
+// diplomailNotificationPublisherAdapter implements
+// `diplomail.NotificationPublisher` by translating each
+// DiplomailNotification into a notification.Intent and routing it
+// through `*notification.Service.Submit`. The publisher leaves the
+// `diplomail.message.received` catalog entry to handle channel
+// fan-out (push only in Stage A).
+type diplomailNotificationPublisherAdapter struct {
+	svc *notification.Service
+}
+
+func (a *diplomailNotificationPublisherAdapter) PublishDiplomailEvent(ctx context.Context, ev diplomail.DiplomailNotification) error {
+	if a == nil || a.svc == nil {
+		return nil
+	}
+	intent := notification.Intent{
+		Kind:           ev.Kind,
+		IdempotencyKey: ev.IdempotencyKey,
+		Recipients:     []uuid.UUID{ev.Recipient},
+		Payload:        ev.Payload,
+	}
+	_, err := a.svc.Submit(ctx, intent)
+	return err
+}

backend/docs/diplomail-translator-setup.md

@@ -0,0 +1,164 @@
+# LibreTranslate setup for diplomatic mail
+
+This document describes how to run the LibreTranslate backend that the
+diplomatic-mail subsystem uses for body translation. The instructions
+target three audiences: developers spinning up LibreTranslate
+alongside `tools/local-dev`, operators preparing a real deployment,
+and reviewers verifying the end-to-end translation flow by hand.
+
+## When you need LibreTranslate
+
+The diplomatic-mail worker runs unconditionally — `make up` and `make
+test` both work without any translator. With
+`BACKEND_DIPLOMAIL_TRANSLATOR_URL` unset, the noop translator
+short-circuits the pipeline: messages are delivered in the original
+language, and the inbox handler returns the original body to every
+reader.
+
+You only need LibreTranslate when you want to exercise the cross-
+language path: sender writes in language X, recipient's
+`accounts.preferred_language` is Y, the worker is expected to fetch
+a Y rendering. The pipeline is otherwise identical and unaware of
+which engine is producing translations.
+
+## Running a local instance
+
+LibreTranslate ships a public Docker image at
+`libretranslate/libretranslate`. The image is ~3 GB on first pull
+because it bundles every supported language model; subsequent runs
+reuse the layer cache.
+
+The simplest setup is a one-shot container:
+
+```bash
+docker run --rm -d --name libretranslate \
+  -p 5000:5000 \
+  -e LT_LOAD_ONLY=en,ru \
+  libretranslate/libretranslate:latest
+```
+
+The `LT_LOAD_ONLY` whitelist trims the loaded model set so the
+container fits in ~600 MB of RAM. Drop the variable to load every
+language pair LibreTranslate ships.
+
+LibreTranslate boots in ~30 seconds (cold) or ~5 seconds (warm
+model cache). Wait until `curl -s http://localhost:5000/languages`
+returns a JSON array before pointing backend at it.
+
+## Wiring backend at it
+
+Add three env vars to the backend process:
+
+```
+BACKEND_DIPLOMAIL_TRANSLATOR_URL=http://localhost:5000
+BACKEND_DIPLOMAIL_TRANSLATOR_TIMEOUT=10s
+BACKEND_DIPLOMAIL_TRANSLATOR_MAX_ATTEMPTS=5
+```
+
+When backend lives inside the `tools/local-dev` Docker network and
+LibreTranslate runs on the host, replace `localhost` with the host's
+docker-bridge address (`http://host.docker.internal:5000` on
+Docker Desktop; `http://172.17.0.1:5000` on a Linux bridge by
+default).
+
+For a stack-internal deployment, drop LibreTranslate into the same
+Docker compose file alongside backend and reach it by its service
+name:
+
+```yaml
+services:
+  libretranslate:
+    image: libretranslate/libretranslate:latest
+    environment:
+      LT_LOAD_ONLY: "en,ru"
+    healthcheck:
+      test: ["CMD", "wget", "-qO-", "http://localhost:5000/languages"]
+      interval: 5s
+      timeout: 2s
+      retries: 12
+
+  backend:
+    environment:
+      BACKEND_DIPLOMAIL_TRANSLATOR_URL: "http://libretranslate:5000"
+    depends_on:
+      libretranslate:
+        condition: service_healthy
+```
+
+## Manual smoke test
+
+Once both services are up:
+
+1. Register two accounts via the public auth flow. Set the second
+   account's `preferred_language` to a value that differs from the
+   sender's writing language (e.g. sender writes in English, second
+   account is `ru`).
+2. Create a private game with the first account, invite the second,
+   land both as active members.
+3. Send a personal message: `POST /api/v1/user/games/{id}/mail/messages`
+   with the body in English.
+4. Watch backend logs for the diplomail worker. After ~2 seconds you
+   should see `translator attempt succeeded` (or equivalent INFO
+   line) and the recipient flipped to `available_at`.
+5. As the second account, fetch
+   `GET /api/v1/user/games/{id}/mail/messages/{message_id}`. The
+   response should carry both `body` (English original) and
+   `translated_body` (Russian) along with the `translation_lang`
+   and `translator` fields.
+
+## Operational notes
+
+- **Resource budget.** With `LT_LOAD_ONLY=en,ru` the container peaks
+  around 800 MB resident; with all languages, ~3 GB. Plan accordingly.
+- **CPU.** LibreTranslate is CPU-bound. One translation of a 200-
+  word body takes ~200 ms on a modern x86 core; the diplomail worker
+  is single-threaded by design, so steady-state throughput is
+  `1 / avg_latency` per backend instance.
+- **Outage behaviour.** A LibreTranslate outage stalls delivery of
+  pending pairs by at most ~31 seconds per pair (the worker's
+  exponential backoff schedule), then falls back to the original
+  body. Inbox listings never depend on the translator's
+  availability.
+- **API key.** Backend does not send an API key. Self-hosted
+  deployments without `LT_API_KEYS` configured accept anonymous
+  POSTs by default, which matches our deployment posture
+  (LibreTranslate sits on the internal docker network, not
+  reachable from outside).
+- **Models.** Adding a new target language is an operator-side
+  task: install the corresponding Argos model into the
+  LibreTranslate container (`argospm install …`) and either restart
+  the container or send a SIGHUP. The diplomail pipeline notices
+  the new language pair automatically — there is no allow-list
+  inside backend.
+
+## Troubleshooting
+
+- **`translator: do request: dial tcp ...: connect: connection refused`.**
+  LibreTranslate is not listening on the configured address. Verify
+  with `curl http://${URL}/languages`. On Docker setups, double-
+  check the bridge address discussion above.
+- **`translator: libretranslate http 400`** in worker logs but the
+  language pair clearly exists.
+  Make sure the request used the two-letter codes (`en`, not
+  `en-US`). Backend normalises before sending; if you see a region
+  subtag in the log, file an issue against `internal/diplomail` —
+  the normalisation should be unconditional.
+- **`translator: libretranslate http 503`.**
+  Container is still loading models. Wait for `/languages` to
+  respond `200`. The worker retries with backoff, so steady-state
+  recovers automatically.
+- **Worker logs only "noop translator returned, delivering
+  fallback".**
+  `BACKEND_DIPLOMAIL_TRANSLATOR_URL` is empty in the backend
+  process. Confirm with `docker compose exec backend env | grep
+  DIPLOMAIL`.
+
+## Future work
+
+- Adding an OpenTelemetry counter and histogram for translator
+  outcomes is tracked in the diplomail package README; the metrics
+  will surface in Grafana once LibreTranslate is deployed.
+- Email-alerting on prolonged outage (e.g. ≥ N consecutive failures
+  in M minutes) is planned through a new
+  `diplomail.translator.unhealthy` notification kind. Not wired
+  yet — current monitoring lives in zap logs.

backend/go.mod

@@ -36,6 +36,7 @@ require (
 )
 
 require (
+	github.com/abadojack/whatlanggo v1.0.1 // indirect
 	github.com/oschwald/geoip2-golang/v2 v2.1.0 // indirect
 	github.com/oschwald/maxminddb-golang/v2 v2.1.1 // indirect
 	github.com/robfig/cron/v3 v3.0.1 // indirect

backend/go.sum

@@ -10,6 +10,8 @@ github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERo
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
 github.com/XSAM/otelsql v0.42.0 h1:Li0xF4eJUxG2e0x3D4rvRlys1f27yJKvjTh7ljkUP5o=
 github.com/XSAM/otelsql v0.42.0/go.mod h1:4mOrEv+cS1KmKzrvTktvJnstr5GtKSAK+QHvFR9OcpI=
+github.com/abadojack/whatlanggo v1.0.1 h1:19N6YogDnf71CTHm3Mp2qhYfkRdyvbgwWdd2EPxJRG4=
+github.com/abadojack/whatlanggo v1.0.1/go.mod h1:66WiQbSbJBIlOZMsvbKe5m6pzQovxCH9B/K8tQB2uoc=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/bytedance/gopkg v0.1.4 h1:oZnQwnX82KAIWb7033bEwtxvTqXcYMxDBaQxo5JJHWM=

backend/internal/auth/auth.go

@@ -76,9 +76,30 @@ func NewService(deps Deps) *Service {
 		// not a security primitive, so a constant key is acceptable.
 		copy(key, []byte("galaxy-backend-auth-fallback-key"))
 	}
+	if deps.Config.DevFixedCode != "" {
+		// Loud, repeated warning so a stray production deployment cannot
+		// claim the operator was unaware. The override is intended for
+		// `tools/local-dev/` and never reaches production binaries in
+		// normal operation.
+		deps.Logger.Warn("DEV-MODE: BACKEND_AUTH_DEV_FIXED_CODE is set; ConfirmEmailCode accepts the literal code in addition to the bcrypt-verified one. NEVER use in production.")
+	}
 	return &Service{deps: deps, emailHashKey: key}
 }
 
+// devFixedCodeMatches reports whether the dev-mode fixed-code override
+// is configured and the submitted code matches it verbatim. The
+// override is opt-in via `BACKEND_AUTH_DEV_FIXED_CODE`; production
+// deployments leave the field empty and devFixedCodeMatches always
+// returns false. See `tools/local-dev/README.md` for the full
+// rationale.
+func (s *Service) devFixedCodeMatches(code string) bool {
+	fixed := s.deps.Config.DevFixedCode
+	if fixed == "" {
+		return false
+	}
+	return code == fixed
+}
+
 // hashEmail returns a stable, hex-encoded HMAC-SHA256 prefix of email
 // suitable for use in structured logs. The key is per-process so the
 // same email maps to the same hash across log lines emitted by this

backend/internal/auth/auth_e2e_test.go

@@ -185,6 +185,35 @@ func authConfig() config.AuthConfig {
 	}
 }
 
+// buildServiceWithConfig wires every dependency around db using cfg as
+// the auth configuration. Returns only the service — assertions on the
+// dev-mode override path do not inspect the recording fakes.
+func buildServiceWithConfig(t *testing.T, db *sql.DB, cfg config.AuthConfig) *auth.Service {
+	t.Helper()
+	store := auth.NewStore(db)
+	cache := auth.NewCache()
+	if err := cache.Warm(context.Background(), store); err != nil {
+		t.Fatalf("warm cache: %v", err)
+	}
+	userStore := user.NewStore(db)
+	userSvc := user.NewService(user.Deps{
+		Store:              userStore,
+		Cache:              user.NewCache(),
+		UserNameMaxRetries: 10,
+		Now:                time.Now,
+	})
+	return auth.NewService(auth.Deps{
+		Store:  store,
+		Cache:  cache,
+		User:   userSvc,
+		Geo:    newStubGeo(),
+		Mail:   newRecordingMailer(),
+		Push:   newRecordingPush(),
+		Config: cfg,
+		Now:    time.Now,
+	})
+}
+
 // buildService wires every dependency around db and returns the service
 // plus the recording fakes for assertions.
 func buildService(t *testing.T, db *sql.DB) (*auth.Service, *recordingMailer, *recordingPush, *stubGeo) {
@@ -412,6 +441,55 @@ func TestSendEmailCodeThrottleReusesChallenge(t *testing.T) {
 	}
 }
 
+func TestConfirmEmailCodeDevFixedCodeBypass(t *testing.T) {
+	db := startPostgres(t)
+	cfg := authConfig()
+	cfg.DevFixedCode = "999999"
+	svc := buildServiceWithConfig(t, db, cfg)
+	ctx := context.Background()
+
+	id, err := svc.SendEmailCode(ctx, "dev-bypass@example.test", "en", "", "")
+	if err != nil {
+		t.Fatalf("send: %v", err)
+	}
+
+	session, err := svc.ConfirmEmailCode(ctx, auth.ConfirmInputs{
+		ChallengeID:     id,
+		Code:            "999999",
+		ClientPublicKey: randomKey(t),
+		TimeZone:        "UTC",
+	})
+	if err != nil {
+		t.Fatalf("ConfirmEmailCode with dev fixed code: %v", err)
+	}
+	if session.DeviceSessionID == uuid.Nil {
+		t.Fatalf("dev fixed code did not produce a session")
+	}
+}
+
+func TestConfirmEmailCodeDevFixedCodeStillRejectsWrong(t *testing.T) {
+	db := startPostgres(t)
+	cfg := authConfig()
+	cfg.DevFixedCode = "999999"
+	svc := buildServiceWithConfig(t, db, cfg)
+	ctx := context.Background()
+
+	id, err := svc.SendEmailCode(ctx, "dev-bypass-wrong@example.test", "en", "", "")
+	if err != nil {
+		t.Fatalf("send: %v", err)
+	}
+
+	_, err = svc.ConfirmEmailCode(ctx, auth.ConfirmInputs{
+		ChallengeID:     id,
+		Code:            "111111",
+		ClientPublicKey: randomKey(t),
+		TimeZone:        "UTC",
+	})
+	if !errors.Is(err, auth.ErrCodeMismatch) {
+		t.Fatalf("ConfirmEmailCode with neither real nor dev code = %v, want ErrCodeMismatch", err)
+	}
+}
+
 func TestConfirmEmailCodeWrongCode(t *testing.T) {
 	db := startPostgres(t)
 	svc, mailer, _, _ := buildService(t, db)

backend/internal/auth/challenge.go

@@ -171,15 +171,21 @@ func (s *Service) ConfirmEmailCode(ctx context.Context, in ConfirmInputs) (Sessi
 		return Session{}, ErrTooManyAttempts
 	}
 
-	if err := verifyCode(loaded.CodeHash, in.Code); err != nil {
+	if !s.devFixedCodeMatches(in.Code) {
-		if errors.Is(err, ErrCodeMismatch) {
+		if err := verifyCode(loaded.CodeHash, in.Code); err != nil {
-			s.deps.Logger.Info("auth challenge code mismatch",
+			if errors.Is(err, ErrCodeMismatch) {
-				zap.String("challenge_id", in.ChallengeID.String()),
+				s.deps.Logger.Info("auth challenge code mismatch",
-				zap.Int32("attempts", loaded.Attempts),
+					zap.String("challenge_id", in.ChallengeID.String()),
-			)
+					zap.Int32("attempts", loaded.Attempts),
-			return Session{}, ErrCodeMismatch
+				)
+				return Session{}, ErrCodeMismatch
+			}
+			return Session{}, err
 		}
-		return Session{}, err
+	} else {
+		s.deps.Logger.Warn("auth challenge accepted via dev-mode fixed code override",
+			zap.String("challenge_id", in.ChallengeID.String()),
+		)
 	}
 
 	// Re-check permanent_block after verifying the code. SendEmailCode

backend/internal/config/config.go

@@ -71,6 +71,7 @@ const (
 	envAuthChallengeThrottleWindow = "BACKEND_AUTH_CHALLENGE_THROTTLE_WINDOW"
 	envAuthChallengeThrottleMax = "BACKEND_AUTH_CHALLENGE_THROTTLE_MAX"
 	envAuthUserNameMaxRetries = "BACKEND_AUTH_USERNAME_MAX_RETRIES"
+	envAuthDevFixedCode = "BACKEND_AUTH_DEV_FIXED_CODE"
 
 	envLobbySweeperInterval = "BACKEND_LOBBY_SWEEPER_INTERVAL"
 	envLobbyPendingRegistrationTTL = "BACKEND_LOBBY_PENDING_REGISTRATION_TTL"
@@ -94,6 +95,18 @@ const (
 	envNotificationAdminEmail = "BACKEND_NOTIFICATION_ADMIN_EMAIL"
 	envNotificationWorkerInterval = "BACKEND_NOTIFICATION_WORKER_INTERVAL"
 	envNotificationMaxAttempts = "BACKEND_NOTIFICATION_MAX_ATTEMPTS"
+
+	envDiplomailMaxBodyBytes = "BACKEND_DIPLOMAIL_MAX_BODY_BYTES"
+	envDiplomailMaxSubjectBytes = "BACKEND_DIPLOMAIL_MAX_SUBJECT_BYTES"
+	envDiplomailTranslatorURL = "BACKEND_DIPLOMAIL_TRANSLATOR_URL"
+	envDiplomailTranslatorTimeout = "BACKEND_DIPLOMAIL_TRANSLATOR_TIMEOUT"
+	envDiplomailTranslatorMaxAttempts = "BACKEND_DIPLOMAIL_TRANSLATOR_MAX_ATTEMPTS"
+	envDiplomailWorkerInterval = "BACKEND_DIPLOMAIL_WORKER_INTERVAL"
+
+	envDevSandboxEmail = "BACKEND_DEV_SANDBOX_EMAIL"
+	envDevSandboxEngineImage = "BACKEND_DEV_SANDBOX_ENGINE_IMAGE"
+	envDevSandboxEngineVersion = "BACKEND_DEV_SANDBOX_ENGINE_VERSION"
+	envDevSandboxPlayerCount = "BACKEND_DEV_SANDBOX_PLAYER_COUNT"
 )
 
 // Default values applied when an environment variable is absent.
@@ -156,6 +169,15 @@ const (
 
 	defaultNotificationWorkerInterval = 5 * time.Second
 	defaultNotificationMaxAttempts = 8
+
+	defaultDiplomailMaxBodyBytes = 4096
+	defaultDiplomailMaxSubjectBytes = 256
+	defaultDiplomailTranslatorTimeout = 10 * time.Second
+	defaultDiplomailTranslatorMaxAttempts = 5
+	defaultDiplomailWorkerInterval = 2 * time.Second
+
+	defaultDevSandboxEngineVersion = "0.1.0"
+	defaultDevSandboxPlayerCount = 20
 )
 
 // Allowed values for the closed-set string options.
@@ -192,12 +214,30 @@ type Config struct {
 	Engine EngineConfig
 	Runtime RuntimeConfig
 	Notification NotificationConfig
+	Diplomail DiplomailConfig
+	DevSandbox DevSandboxConfig
 
 	// FreshnessWindow mirrors the gateway freshness window and is used by the
 	// push server to bound the cursor TTL.
 	FreshnessWindow time.Duration
 }
 
+// DevSandboxConfig configures the boot-time bootstrap implemented in
+// `backend/internal/devsandbox`. When Email is empty the bootstrap
+// is a no-op, which is the production posture. When Email is set —
+// from `BACKEND_DEV_SANDBOX_EMAIL` in the `tools/local-dev` stack —
+// the bootstrap idempotently provisions a real user, the configured
+// number of dummy participants, a private "Dev Sandbox" game, the
+// matching memberships, and drives the lifecycle to `running`. The
+// engine image and engine version refer to a row that the bootstrap
+// also seeds in `engine_versions`.
+type DevSandboxConfig struct {
+	Email string
+	EngineImage string
+	EngineVersion string
+	PlayerCount int
+}
+
 // LoggingConfig stores the parameters used by the structured logger.
 type LoggingConfig struct {
 	// Level is the zap level name (e.g. "debug", "info", "warn", "error").
@@ -293,6 +333,16 @@ type AuthConfig struct {
 	ChallengeMaxAttempts int
 	ChallengeThrottle AuthChallengeThrottleConfig
 	UserNameMaxRetries int
+
+	// DevFixedCode, when non-empty, makes ConfirmEmailCode accept this
+	// literal as a valid code in addition to the bcrypt-verified one
+	// stored on the challenge row. The override is intended for the
+	// `tools/local-dev` stack so a developer can log in without
+	// reading codes out of Mailpit. The variable MUST stay unset in
+	// production: validation requires a six-digit decimal value, and
+	// the auth service emits a loud startup warning when it picks the
+	// override up.
+	DevFixedCode string
 }
 
 // AuthChallengeThrottleConfig bounds how many un-consumed, non-expired
@@ -361,6 +411,42 @@ type RuntimeConfig struct {
 	StopGracePeriod time.Duration
 }
 
+// DiplomailConfig bounds the diplomatic-mail subsystem. Both limits
+// are enforced in the service layer, so they can be tuned at runtime
+// without a schema migration. Body and subject are stored as plain
+// UTF-8 text; HTML is neither parsed nor sanitised on the server.
+type DiplomailConfig struct {
+	// MaxBodyBytes caps the length of `diplomail_messages.body` in
+	// bytes (not runes). A send whose body exceeds the limit is
+	// rejected with ErrInvalidInput.
+	MaxBodyBytes int
+
+	// MaxSubjectBytes caps the length of `diplomail_messages.subject`
+	// in bytes. Subjects are optional; the empty-string default
+	// passes the limit trivially.
+	MaxSubjectBytes int
+
+	// TranslatorURL is the base URL of the LibreTranslate-compatible
+	// instance the async translation worker calls. When empty, the
+	// worker still runs but falls through to "deliver original"
+	// (the noop translator returns engine=noop).
+	TranslatorURL string
+
+	// TranslatorTimeout bounds a single HTTP request to the
+	// translator. Worker retries (exponential backoff up to
+	// TranslatorMaxAttempts) layer on top.
+	TranslatorTimeout time.Duration
+
+	// TranslatorMaxAttempts is the number of times the worker tries
+	// to translate one (message, target_lang) pair before falling
+	// back to delivering the original body.
+	TranslatorMaxAttempts int
+
+	// WorkerInterval bounds how often the async translation worker
+	// scans for pending pairs. The worker handles one pair per tick.
+	WorkerInterval time.Duration
+}
+
 // NotificationConfig configures the notification fan-out module
 // implemented in `backend/internal/notification`. AdminEmail receives
 // admin-channel kinds (the `runtime.*` set in `backend/README.md` §10);
@@ -458,6 +544,17 @@ func DefaultConfig() Config {
 			WorkerInterval: defaultNotificationWorkerInterval,
 			MaxAttempts: defaultNotificationMaxAttempts,
 		},
+		Diplomail: DiplomailConfig{
+			MaxBodyBytes: defaultDiplomailMaxBodyBytes,
+			MaxSubjectBytes: defaultDiplomailMaxSubjectBytes,
+			TranslatorTimeout: defaultDiplomailTranslatorTimeout,
+			TranslatorMaxAttempts: defaultDiplomailTranslatorMaxAttempts,
+			WorkerInterval: defaultDiplomailWorkerInterval,
+		},
+		DevSandbox: DevSandboxConfig{
+			EngineVersion: defaultDevSandboxEngineVersion,
+			PlayerCount: defaultDevSandboxPlayerCount,
+		},
 		Runtime: RuntimeConfig{
 			WorkerPoolSize: defaultRuntimeWorkerPoolSize,
 			JobQueueSize: defaultRuntimeJobQueueSize,
@@ -566,6 +663,7 @@ func LoadFromEnv() (Config, error) {
 	if cfg.Auth.UserNameMaxRetries, err = loadInt(envAuthUserNameMaxRetries, cfg.Auth.UserNameMaxRetries); err != nil {
 		return Config{}, err
 	}
+	cfg.Auth.DevFixedCode = loadString(envAuthDevFixedCode, cfg.Auth.DevFixedCode)
 
 	if cfg.Lobby.SweeperInterval, err = loadDuration(envLobbySweeperInterval, cfg.Lobby.SweeperInterval); err != nil {
 		return Config{}, err
@@ -616,6 +714,30 @@ func LoadFromEnv() (Config, error) {
 		return Config{}, err
 	}
 
+	if cfg.Diplomail.MaxBodyBytes, err = loadInt(envDiplomailMaxBodyBytes, cfg.Diplomail.MaxBodyBytes); err != nil {
+		return Config{}, err
+	}
+	if cfg.Diplomail.MaxSubjectBytes, err = loadInt(envDiplomailMaxSubjectBytes, cfg.Diplomail.MaxSubjectBytes); err != nil {
+		return Config{}, err
+	}
+	cfg.Diplomail.TranslatorURL = loadString(envDiplomailTranslatorURL, cfg.Diplomail.TranslatorURL)
+	if cfg.Diplomail.TranslatorTimeout, err = loadDuration(envDiplomailTranslatorTimeout, cfg.Diplomail.TranslatorTimeout); err != nil {
+		return Config{}, err
+	}
+	if cfg.Diplomail.TranslatorMaxAttempts, err = loadInt(envDiplomailTranslatorMaxAttempts, cfg.Diplomail.TranslatorMaxAttempts); err != nil {
+		return Config{}, err
+	}
+	if cfg.Diplomail.WorkerInterval, err = loadDuration(envDiplomailWorkerInterval, cfg.Diplomail.WorkerInterval); err != nil {
+		return Config{}, err
+	}
+
+	cfg.DevSandbox.Email = strings.TrimSpace(loadString(envDevSandboxEmail, cfg.DevSandbox.Email))
+	cfg.DevSandbox.EngineImage = strings.TrimSpace(loadString(envDevSandboxEngineImage, cfg.DevSandbox.EngineImage))
+	cfg.DevSandbox.EngineVersion = strings.TrimSpace(loadString(envDevSandboxEngineVersion, cfg.DevSandbox.EngineVersion))
+	if cfg.DevSandbox.PlayerCount, err = loadInt(envDevSandboxPlayerCount, cfg.DevSandbox.PlayerCount); err != nil {
+		return Config{}, err
+	}
+
 	if err := cfg.Validate(); err != nil {
 		return Config{}, err
 	}
@@ -745,6 +867,11 @@ func (c Config) Validate() error {
 	if c.Auth.UserNameMaxRetries <= 0 {
 		return fmt.Errorf("%s must be positive", envAuthUserNameMaxRetries)
 	}
+	if c.Auth.DevFixedCode != "" {
+		if !isDecimalString(c.Auth.DevFixedCode, 6) {
+			return fmt.Errorf("%s must be a six-digit decimal string when set", envAuthDevFixedCode)
+		}
+	}
 
 	if c.Lobby.SweeperInterval <= 0 {
 		return fmt.Errorf("%s must be positive", envLobbySweeperInterval)
@@ -800,15 +927,58 @@ func (c Config) Validate() error {
 	if c.Notification.MaxAttempts <= 0 {
 		return fmt.Errorf("%s must be positive", envNotificationMaxAttempts)
 	}
+
+	if c.Diplomail.MaxBodyBytes <= 0 {
+		return fmt.Errorf("%s must be positive", envDiplomailMaxBodyBytes)
+	}
+	if c.Diplomail.MaxSubjectBytes < 0 {
+		return fmt.Errorf("%s must not be negative", envDiplomailMaxSubjectBytes)
+	}
+	if c.Diplomail.TranslatorTimeout <= 0 {
+		return fmt.Errorf("%s must be positive", envDiplomailTranslatorTimeout)
+	}
+	if c.Diplomail.TranslatorMaxAttempts <= 0 {
+		return fmt.Errorf("%s must be positive", envDiplomailTranslatorMaxAttempts)
+	}
+	if c.Diplomail.WorkerInterval <= 0 {
+		return fmt.Errorf("%s must be positive", envDiplomailWorkerInterval)
+	}
 	if email := strings.TrimSpace(c.Notification.AdminEmail); email != "" {
 		if _, err := netmail.ParseAddress(email); err != nil {
 			return fmt.Errorf("%s must be a valid RFC 5322 address: %w", envNotificationAdminEmail, err)
 		}
 	}
 
+	if email := strings.TrimSpace(c.DevSandbox.Email); email != "" {
+		if _, err := netmail.ParseAddress(email); err != nil {
+			return fmt.Errorf("%s must be a valid RFC 5322 address: %w", envDevSandboxEmail, err)
+		}
+		if strings.TrimSpace(c.DevSandbox.EngineImage) == "" {
+			return fmt.Errorf("%s must not be empty when %s is set", envDevSandboxEngineImage, envDevSandboxEmail)
+		}
+		if strings.TrimSpace(c.DevSandbox.EngineVersion) == "" {
+			return fmt.Errorf("%s must not be empty when %s is set", envDevSandboxEngineVersion, envDevSandboxEmail)
+		}
+		if c.DevSandbox.PlayerCount <= 0 {
+			return fmt.Errorf("%s must be positive when %s is set", envDevSandboxPlayerCount, envDevSandboxEmail)
+		}
+	}
+
 	return nil
 }
 
+func isDecimalString(value string, length int) bool {
+	if len(value) != length {
+		return false
+	}
+	for _, r := range value {
+		if r < '0' || r > '9' {
+			return false
+		}
+	}
+	return true
+}
+
 func loadString(name, fallback string) string {
 	raw, ok := os.LookupEnv(name)
 	if !ok {

backend/internal/config/config_test.go

@@ -77,6 +77,40 @@ func TestValidateRejectsUnknownTracesExporter(t *testing.T) {
 	}
 }
 
+func TestLoadFromEnvAcceptsDevFixedCode(t *testing.T) {
+	env := validEnv()
+	env["BACKEND_AUTH_DEV_FIXED_CODE"] = "123456"
+	setEnv(t, env)
+
+	cfg, err := LoadFromEnv()
+	if err != nil {
+		t.Fatalf("LoadFromEnv returned error: %v", err)
+	}
+	if cfg.Auth.DevFixedCode != "123456" {
+		t.Fatalf("Auth.DevFixedCode = %q, want \"123456\"", cfg.Auth.DevFixedCode)
+	}
+}
+
+func TestValidateRejectsDevFixedCodeWrongLength(t *testing.T) {
+	env := validEnv()
+	env["BACKEND_AUTH_DEV_FIXED_CODE"] = "12345"
+	setEnv(t, env)
+
+	if _, err := LoadFromEnv(); err == nil || !strings.Contains(err.Error(), "BACKEND_AUTH_DEV_FIXED_CODE") {
+		t.Fatalf("expected DEV fixed-code length error, got %v", err)
+	}
+}
+
+func TestValidateRejectsDevFixedCodeNonDecimal(t *testing.T) {
+	env := validEnv()
+	env["BACKEND_AUTH_DEV_FIXED_CODE"] = "abcdef"
+	setEnv(t, env)
+
+	if _, err := LoadFromEnv(); err == nil || !strings.Contains(err.Error(), "BACKEND_AUTH_DEV_FIXED_CODE") {
+		t.Fatalf("expected DEV fixed-code decimal error, got %v", err)
+	}
+}
+
 func TestValidateRejectsPrometheusWithoutAddr(t *testing.T) {
 	cfg := DefaultConfig()
 	cfg.Postgres.DSN = "postgres://x:y@127.0.0.1/galaxy"

backend/internal/devsandbox/bootstrap.go

@@ -0,0 +1,287 @@
+// Package devsandbox provisions a ready-to-play game on backend boot
+// for the `tools/local-dev` stack.
+//
+// Bootstrap is invoked from `backend/cmd/backend/main.go` after the
+// admin bootstrap and before the HTTP listener starts. It reads
+// `cfg.DevSandbox`; when `Email` is empty (the production posture)
+// the function logs "skipped" and returns nil. When set, it
+// idempotently:
+//
+//   1. registers the configured engine version and image;
+//   2. find-or-creates the real dev user with the configured email;
+//   3. find-or-creates `cfg.PlayerCount - 1` deterministic dummy
+//      users so the engine's minimum-players constraint is met;
+//   4. find-or-creates a private "Dev Sandbox" game owned by the
+//      real user with min/max_players = cfg.PlayerCount and a
+//      year-out turn schedule (effectively frozen at turn 1);
+//   5. inserts memberships for all participants bypassing the
+//      application/approval flow;
+//   6. drives the lifecycle to `running` (or as far as possible if
+//      the runtime is busy).
+//
+// The function is a no-op on subsequent boots once the game is
+// running; partial states from earlier crashes are recovered.
+package devsandbox
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"galaxy/backend/internal/config"
+	"galaxy/backend/internal/lobby"
+	"galaxy/backend/internal/runtime"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// SandboxGameName is the display name used to identify the
+// auto-provisioned game on subsequent reboots. The combination of
+// game_name and owner_user_id is unique enough in practice — only
+// the dev sandbox bootstrap creates a game owned by the configured
+// real user with this exact name.
+const SandboxGameName = "Dev Sandbox"
+
+// SandboxTurnSchedule keeps the game on turn 1 by scheduling the
+// next turn a year out. The runtime scheduler still parses this and
+// will tick once a year — long enough to never interfere with
+// solo UI development.
+const SandboxTurnSchedule = "0 0 1 1 *"
+
+// UserEnsurer matches `auth.UserEnsurer`. We define a local
+// interface to avoid importing the auth package and circular
+// dependencies — the production wiring passes the same `*user.Service`
+// instance used by auth.
+type UserEnsurer interface {
+	EnsureByEmail(ctx context.Context, email, preferredLanguage, timeZone, declaredCountry string) (uuid.UUID, error)
+}
+
+// Deps aggregates the collaborators Bootstrap needs.
+type Deps struct {
+	Users          UserEnsurer
+	Lobby          *lobby.Service
+	EngineVersions *runtime.EngineVersionService
+}
+
+// Bootstrap runs the seven-step provisioning flow described on the
+// package doc comment. Errors are returned to the caller; the boot
+// path in `cmd/backend/main.go` aborts startup if Bootstrap fails so
+// a misconfigured dev environment surfaces immediately rather than
+// silently leaving the lobby empty.
+func Bootstrap(ctx context.Context, deps Deps, cfg config.DevSandboxConfig, logger *zap.Logger) error {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	logger = logger.Named("dev_sandbox")
+
+	if cfg.Email == "" {
+		logger.Info("skipped (no email)")
+		return nil
+	}
+	if deps.Users == nil || deps.Lobby == nil || deps.EngineVersions == nil {
+		return errors.New("dev_sandbox: deps.Users, deps.Lobby and deps.EngineVersions are required")
+	}
+	if cfg.PlayerCount <= 0 {
+		return fmt.Errorf("dev_sandbox: PlayerCount must be positive, got %d", cfg.PlayerCount)
+	}
+
+	if err := ensureEngineVersion(ctx, deps.EngineVersions, cfg, logger); err != nil {
+		return err
+	}
+
+	realID, err := deps.Users.EnsureByEmail(ctx, cfg.Email, "en", "UTC", "")
+	if err != nil {
+		return fmt.Errorf("dev_sandbox: ensure real user: %w", err)
+	}
+
+	dummyIDs := make([]uuid.UUID, 0, cfg.PlayerCount-1)
+	for i := 1; i < cfg.PlayerCount; i++ {
+		email := fmt.Sprintf("dev-dummy-%02d@local.test", i)
+		id, err := deps.Users.EnsureByEmail(ctx, email, "en", "UTC", "")
+		if err != nil {
+			return fmt.Errorf("dev_sandbox: ensure dummy %d: %w", i, err)
+		}
+		dummyIDs = append(dummyIDs, id)
+	}
+
+	if err := purgeTerminalSandboxGames(ctx, deps.Lobby, realID, logger); err != nil {
+		return err
+	}
+
+	game, err := findOrCreateSandboxGame(ctx, deps.Lobby, realID, cfg)
+	if err != nil {
+		return err
+	}
+
+	game, err = ensureMembershipsAndDrive(ctx, deps.Lobby, game, realID, dummyIDs, logger)
+	if err != nil {
+		return err
+	}
+
+	logger.Info("bootstrap complete",
+		zap.String("user_id", realID.String()),
+		zap.String("game_id", game.GameID.String()),
+		zap.String("status", game.Status),
+	)
+	return nil
+}
+
+func ensureEngineVersion(ctx context.Context, svc *runtime.EngineVersionService, cfg config.DevSandboxConfig, logger *zap.Logger) error {
+	_, err := svc.Register(ctx, runtime.RegisterInput{
+		Version:  cfg.EngineVersion,
+		ImageRef: cfg.EngineImage,
+	})
+	switch {
+	case err == nil:
+		logger.Info("engine version registered",
+			zap.String("version", cfg.EngineVersion),
+			zap.String("image", cfg.EngineImage),
+		)
+		return nil
+	case errors.Is(err, runtime.ErrEngineVersionTaken):
+		logger.Debug("engine version already registered",
+			zap.String("version", cfg.EngineVersion),
+		)
+		return nil
+	default:
+		return fmt.Errorf("dev_sandbox: register engine version: %w", err)
+	}
+}
+
+// terminalSandboxStatus reports whether a sandbox game has reached a
+// state from which it can no longer be driven back to running. We
+// treat such games as "absent" so the next bootstrap creates a fresh
+// one rather than handing the developer a dead lobby tile.
+func terminalSandboxStatus(status string) bool {
+	switch status {
+	case lobby.GameStatusCancelled, lobby.GameStatusFinished, lobby.GameStatusStartFailed:
+		return true
+	}
+	return false
+}
+
+// purgeTerminalSandboxGames deletes every previous "Dev Sandbox" game
+// the dev user owns that has reached a terminal state
+// (cancelled / finished / start_failed). The cascade declared in
+// `00001_init.sql` removes the matching memberships, applications,
+// invites, runtime records, and player mappings in the same write,
+// so the developer's lobby never piles up dead tiles between
+// `make rebuild` cycles. Non-terminal games are left untouched —
+// a `running` sandbox from a previous boot is the happy path.
+func purgeTerminalSandboxGames(ctx context.Context, svc *lobby.Service, ownerID uuid.UUID, logger *zap.Logger) error {
+	games, err := svc.ListMyGames(ctx, ownerID)
+	if err != nil {
+		return fmt.Errorf("dev_sandbox: list my games: %w", err)
+	}
+	for _, g := range games {
+		if g.GameName != SandboxGameName || g.OwnerUserID == nil || *g.OwnerUserID != ownerID {
+			continue
+		}
+		if !terminalSandboxStatus(g.Status) {
+			continue
+		}
+		if err := svc.DeleteGame(ctx, g.GameID); err != nil {
+			return fmt.Errorf("dev_sandbox: delete terminal sandbox %s: %w", g.GameID, err)
+		}
+		logger.Info("purged terminal sandbox game",
+			zap.String("game_id", g.GameID.String()),
+			zap.String("status", g.Status),
+		)
+	}
+	return nil
+}
+
+func findOrCreateSandboxGame(ctx context.Context, svc *lobby.Service, ownerID uuid.UUID, cfg config.DevSandboxConfig) (lobby.GameRecord, error) {
+	games, err := svc.ListMyGames(ctx, ownerID)
+	if err != nil {
+		return lobby.GameRecord{}, fmt.Errorf("dev_sandbox: list my games: %w", err)
+	}
+	for _, g := range games {
+		if g.GameName != SandboxGameName || g.OwnerUserID == nil || *g.OwnerUserID != ownerID {
+			continue
+		}
+		// `purgeTerminalSandboxGames` ran before us, so any sandbox
+		// game still in the list is either a live one we should
+		// reuse or a transient state we can drive forward.
+		return g, nil
+	}
+	rec, err := svc.CreateGame(ctx, lobby.CreateGameInput{
+		OwnerUserID:         &ownerID,
+		Visibility:          lobby.VisibilityPrivate,
+		GameName:            SandboxGameName,
+		Description:         "Auto-provisioned by backend/internal/devsandbox for solo UI development.",
+		MinPlayers:          int32(cfg.PlayerCount),
+		MaxPlayers:          int32(cfg.PlayerCount),
+		StartGapHours:       0,
+		StartGapPlayers:     0,
+		EnrollmentEndsAt:    time.Now().Add(365 * 24 * time.Hour),
+		TurnSchedule:        SandboxTurnSchedule,
+		TargetEngineVersion: cfg.EngineVersion,
+	})
+	if err != nil {
+		return lobby.GameRecord{}, fmt.Errorf("dev_sandbox: create game: %w", err)
+	}
+	return rec, nil
+}
+
+func ensureMembershipsAndDrive(ctx context.Context, svc *lobby.Service, game lobby.GameRecord, realID uuid.UUID, dummyIDs []uuid.UUID, logger *zap.Logger) (lobby.GameRecord, error) {
+	caller := realID
+	if game.Status == lobby.GameStatusDraft {
+		next, err := svc.OpenEnrollment(ctx, &caller, false, game.GameID)
+		if err != nil {
+			return game, fmt.Errorf("dev_sandbox: open enrollment: %w", err)
+		}
+		game = next
+	}
+
+	if game.Status == lobby.GameStatusEnrollmentOpen {
+		users := append([]uuid.UUID{realID}, dummyIDs...)
+		for i, uid := range users {
+			raceName := fmt.Sprintf("Sandbox-%02d", i+1)
+			if _, err := svc.InsertMembershipDirect(ctx, lobby.InsertMembershipDirectInput{
+				GameID:   game.GameID,
+				UserID:   uid,
+				RaceName: raceName,
+			}); err != nil {
+				return game, fmt.Errorf("dev_sandbox: insert membership %d: %w", i+1, err)
+			}
+		}
+		logger.Info("memberships ensured",
+			zap.Int("count", len(users)),
+			zap.String("game_id", game.GameID.String()),
+		)
+		next, err := svc.ReadyToStart(ctx, &caller, false, game.GameID)
+		if err != nil {
+			return game, fmt.Errorf("dev_sandbox: ready to start: %w", err)
+		}
+		game = next
+	}
+
+	if game.Status == lobby.GameStatusReadyToStart {
+		next, err := svc.Start(ctx, &caller, false, game.GameID)
+		if err != nil {
+			return game, fmt.Errorf("dev_sandbox: start: %w", err)
+		}
+		game = next
+	}
+
+	if game.Status == lobby.GameStatusStartFailed {
+		next, err := svc.RetryStart(ctx, &caller, false, game.GameID)
+		if err != nil {
+			logger.Warn("retry start failed", zap.Error(err))
+			return game, nil
+		}
+		game = next
+		if game.Status == lobby.GameStatusReadyToStart {
+			next, err := svc.Start(ctx, &caller, false, game.GameID)
+			if err != nil {
+				return game, fmt.Errorf("dev_sandbox: start after retry: %w", err)
+			}
+			game = next
+		}
+	}
+
+	return game, nil
+}

backend/internal/devsandbox/bootstrap_test.go

@@ -0,0 +1,106 @@
+package devsandbox
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"galaxy/backend/internal/config"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// TestBootstrapSkippedWhenEmailEmpty exercises the no-op branch: with
+// the production posture (Email == "") Bootstrap must return without
+// touching any dependency. The fact that Users/Lobby/EngineVersions
+// are nil here doubles as a check that the early-return runs first.
+func TestBootstrapSkippedWhenEmailEmpty(t *testing.T) {
+	err := Bootstrap(
+		context.Background(),
+		Deps{},
+		config.DevSandboxConfig{},
+		zap.NewNop(),
+	)
+	if err != nil {
+		t.Fatalf("expected nil error on empty email, got: %v", err)
+	}
+}
+
+// TestBootstrapRejectsZeroPlayerCount confirms the validation
+// short-circuits the flow before any DB call when PlayerCount is
+// non-positive but Email is set. The error path is fast and never
+// dereferences the (still-nil) Users/Lobby deps.
+func TestBootstrapRejectsZeroPlayerCount(t *testing.T) {
+	err := Bootstrap(
+		context.Background(),
+		Deps{Users: stubEnsurer{}, Lobby: nil, EngineVersions: nil},
+		config.DevSandboxConfig{
+			Email:         "dev@local.test",
+			EngineImage:   "galaxy-engine:local-dev",
+			EngineVersion: "0.0.0-local-dev",
+			PlayerCount:   0,
+		},
+		zap.NewNop(),
+	)
+	if err == nil {
+		t.Fatal("expected error on zero PlayerCount, got nil")
+	}
+}
+
+// TestBootstrapRejectsMissingDeps checks that a misconfigured wiring
+// (Email set but one of the required services nil) fails fast rather
+// than panicking when the bootstrap reaches its first service call.
+func TestBootstrapRejectsMissingDeps(t *testing.T) {
+	err := Bootstrap(
+		context.Background(),
+		Deps{Users: stubEnsurer{}, Lobby: nil, EngineVersions: nil},
+		config.DevSandboxConfig{
+			Email:         "dev@local.test",
+			EngineImage:   "galaxy-engine:local-dev",
+			EngineVersion: "0.0.0-local-dev",
+			PlayerCount:   20,
+		},
+		zap.NewNop(),
+	)
+	if err == nil {
+		t.Fatal("expected error on missing deps, got nil")
+	}
+	if !errors.Is(err, errMissingDepsSentinel) && err.Error() == "" {
+		// The exact wording is not part of the contract; this branch
+		// only asserts the error is non-nil and human-readable.
+		t.Fatalf("error has empty message: %v", err)
+	}
+}
+
+// errMissingDepsSentinel exists so the assertion above can compile;
+// the real error is constructed via errors.New inside Bootstrap and
+// is intentionally not exported. The test only needs to confirm the
+// returned error has a message.
+var errMissingDepsSentinel = errors.New("sentinel")
+
+// TestTerminalSandboxStatus pins the contract that decides whether a
+// previously created sandbox game gets purged on the next boot.
+// Terminal states are deleted (cascade-style) so the developer's
+// lobby never piles up dead tiles between `make rebuild` cycles.
+func TestTerminalSandboxStatus(t *testing.T) {
+	terminal := []string{"cancelled", "finished", "start_failed"}
+	live := []string{"draft", "enrollment_open", "ready_to_start", "starting", "running", "paused"}
+
+	for _, status := range terminal {
+		if !terminalSandboxStatus(status) {
+			t.Errorf("expected %q to be terminal", status)
+		}
+	}
+	for _, status := range live {
+		if terminalSandboxStatus(status) {
+			t.Errorf("expected %q to be non-terminal", status)
+		}
+	}
+}
+
+type stubEnsurer struct{}
+
+func (stubEnsurer) EnsureByEmail(_ context.Context, _, _, _, _ string) (uuid.UUID, error) {
+	return uuid.UUID{}, nil
+}

backend/internal/diplomail/README.md

@@ -0,0 +1,196 @@
+# diplomail
+
+`diplomail` owns the diplomatic-mail subsystem of the Galaxy backend
+service. Messages live in the lobby-side domain (their storage and
+lifecycle are tied to a game), but they are surfaced inside the game UI
+— the lobby exposes only an unread-count badge per game.
+
+## Stages
+
+The package ships in four staged increments. Stage A is the surface
+described below; the remaining stages add admin / system mail,
+lifecycle hooks, paid-tier broadcast, multi-game broadcast, bulk
+purge, and the language-detection / translation cache.
+
+| Stage | Scope | Status |
+|-------|-------|--------|
+| A | Schema, personal single-recipient send / read / delete, unread badge, push event with body-language `und` | shipped |
+| B | Owner / admin sends + lifecycle hooks (paused, cancelled, kick); strict soft-access for kicked players | shipped |
+| C | Paid-tier personal broadcast + admin multi-game broadcast + bulk purge + admin observability | shipped |
+| D | Body-language detection (whatlanggo) + translation cache + lazy per-read translator dispatch | shipped |
+| E | LibreTranslate HTTP client + async translation worker with exponential backoff + delivery gating on translation completion | shipped |
+
+## Tables
+
+Three Postgres tables in the `backend` schema:
+
+- `diplomail_messages` — one row per send (personal, admin, or
+  system). Captures `game_name` and IP at insert time so audit
+  rendering survives renames and purges.
+- `diplomail_recipients` — one row per (message, recipient). Holds
+  per-user `read_at`, `deleted_at`, `delivered_at`, `notified_at`
+  state. Snapshot fields (`recipient_user_name`,
+  `recipient_race_name`) are captured at insert time and survive
+  membership revocation.
+- `diplomail_translations` — cached per (message, target_lang)
+  rendering. One translation is reused across every recipient that
+  asks for that language.
+
+## Permissions
+
+| Action | Caller | Pre-conditions |
+|--------|--------|----------------|
+| Send personal | user | active membership in game; recipient is active member |
+| Paid-tier broadcast | paid-tier user | active membership; recipients = every other active member |
+| Send admin (single user) | game owner OR site admin | recipient is any-status member of the game |
+| Send admin (broadcast) | game owner OR site admin | recipient scope ∈ `active` / `active_and_removed` / `all_members`; sender excluded |
+| Multi-game admin broadcast | site admin | scope `selected` (with `game_ids`) or `all_running` |
+| Bulk purge | site admin | `older_than_years >= 1`; targets games with terminal status finished more than N years ago |
+| Read message | the recipient | row exists in `diplomail_recipients(message_id, user_id)`; non-active members see admin-kind only |
+| Mark read | the recipient | row exists; idempotent if already marked |
+| Soft delete | the recipient | `read_at IS NOT NULL` (open-then-delete, item 10) |
+
+Stage D will add body-language detection (whatlanggo) and the
+translation cache + async worker.
+
+System mail is produced internally by lobby lifecycle hooks:
+`Service.transition()` emits `game.paused` / `game.cancelled` system
+mail to every active member; `Service.changeMembershipStatus` /
+`Service.AdminBanMember` emit `membership.removed` /
+`membership.blocked` system mail addressed to the affected user.
+
+## Content rules
+
+- Body is plain UTF-8 text. The server does **not** parse, sanitise,
+  or escape HTML — the UI renders messages via `textContent`.
+- Body length is capped by `BACKEND_DIPLOMAIL_MAX_BODY_BYTES` (default
+  4096). Subject length is capped by
+  `BACKEND_DIPLOMAIL_MAX_SUBJECT_BYTES` (default 256). Both limits
+  live in the service layer so they can be tuned without a schema
+  migration.
+- `body_lang` is filled at send time by the configured
+  `detector.LanguageDetector` (default: `whatlanggo`, body-only,
+  ≥ 25 runes; shorter bodies stay `und`).
+
+## Translation
+
+Stage D adds a lazy translation cache. When a recipient reads a
+message through `GET /api/v1/user/games/{game_id}/mail/messages/{id}`,
+the handler resolves the caller's `accounts.preferred_language` and
+asks `Service.GetMessage(…, targetLang)` to attach a translation:
+
+- on cache hit (row in `diplomail_translations`), the rendering is
+  returned directly under `translated_subject` / `translated_body`;
+- on cache miss, the configured `translator.Translator` is invoked.
+  A non-noop result is persisted and returned to the caller; the
+  noop translator that ships with Stage D returns `engine == "noop"`,
+  which is treated as "translation unavailable" and the caller falls
+  back to the original body.
+
+The inbox listing (`/inbox`) reuses cached translations but never
+calls the translator on miss — bulk listings stay fast even when a
+real translator (LibreTranslate, SaaS engine) introduces I/O cost.
+
+Future work plugs a real `translator.Translator` (LibreTranslate
+HTTP client is the documented next step) without touching the rest
+of the system.
+
+## Async translation (Stage E)
+
+Stage E switches the translation pipeline from "lazy at read" to
+"async at send". The send path stays synchronous from the
+caller's perspective: the message and recipient rows are inserted
+in one transaction. What changes is delivery semantics:
+
+- Recipients whose `preferred_language` matches the detected
+  `body_lang` (or whose body language is `und`) get
+  `available_at = now()` straight away and the push event fires
+  during the request.
+- Recipients whose `preferred_language` differs are inserted with
+  `available_at IS NULL`. They are **not** visible in inbox, unread
+  count, or push events until the worker translates the message.
+
+The worker (`internal/diplomail.Worker`, started as an
+`app.Component` in `cmd/backend/main`) ticks once every
+`BACKEND_DIPLOMAIL_WORKER_INTERVAL` (default `2s`). Each tick:
+
+1. Picks one distinct `(message_id, recipient_preferred_language)`
+   pair from `diplomail_recipients` where `available_at IS NULL`
+   and `next_translation_attempt_at` is unset or due.
+2. Loads the source message, checks the translation cache.
+3. On cache hit → marks every pending recipient of the pair
+   delivered and emits push.
+4. On cache miss → asks the configured `Translator`:
+   - success → caches the translation, marks delivered, push;
+   - HTTP 400 (unsupported pair) → marks delivered without a
+     translation (fallback to original);
+   - other failure → bumps `translation_attempts`, schedules the
+     retry via `next_translation_attempt_at`, leaves pending.
+5. After `BACKEND_DIPLOMAIL_TRANSLATOR_MAX_ATTEMPTS` (default `5`)
+   the worker falls back to delivering the original body so a
+   prolonged LibreTranslate outage does not strand messages.
+
+Retry backoff is exponential `1s → 2s → 4s → 8s → 16s` (capped at
+60s) per pair. Operators monitor the LibreTranslate dependency
+through standard OpenTelemetry export — translation outcomes
+surface in `diplomail.worker` logs at Info / Warn levels;
+Grafana / Prometheus dashboards live outside this package.
+
+### Multi-instance posture (known limitation)
+
+`PickPendingTranslationPair` intentionally drops `FOR UPDATE`: the
+worker is single-threaded per process, and we did not want a slow
+LibreTranslate HTTP call to keep a row-lock open. The cost is a
+small window where two backend instances pulling at the same
+moment can both claim the same pair: the cache-write side stays
+clean (`INSERT … ON CONFLICT DO NOTHING`), but each instance will
+publish its own push event to every recipient of the pair, so the
+duplicate push is the visible failure mode.
+
+The current deployment runs a single backend instance and the
+window does not exist. When the platform scales to multiple
+instances, we will revisit the pickup query — either by holding
+the lock through the HTTP call (with a short timeout to bound the
+worst case) or by introducing a `claimed_at` column and a
+short-lived advisory lease. The change is local to this package
+and does not affect callers.
+
+For the LibreTranslate operational recipe — installing, wiring,
+manual smoke test — see
+[`backend/docs/diplomail-translator-setup.md`](../../docs/diplomail-translator-setup.md).
+
+## Push integration
+
+Every successful send emits a `diplomail.message.received` push
+intent through the existing notification pipeline. The catalog entry
+limits delivery to the push channel — email is intentionally absent;
+the inbox endpoint is the durable fallback for offline users. The
+payload includes the recipient's freshly recomputed unread count for
+the lobby badge and for the in-game header.
+
+## Lifecycle hooks (Stage B)
+
+The lobby module is the producer of system mail. Stage B will add a
+`DiplomailPublisher` collaborator on `lobby.Service` and call it on
+`paused` / `cancelled` transitions and on `BlockMembership` /
+`AdminBanMember`. The publisher constructs a
+`kind='admin', sender_kind='system'` message with a templated body;
+the recipient receives the durable copy in their inbox even after the
+membership is revoked.
+
+If a future stage adds inactivity-based player removal at the lobby
+sweeper, that path **must** call the same publisher so the kicked
+player has the explanation in their inbox.
+
+## Wiring
+
+`cmd/backend/main.go` constructs `*diplomail.Service` with three
+collaborators:
+
+- `*Store` over the shared Postgres pool;
+- `MembershipLookup` adapter that walks the lobby cache for the
+  active `(game_id, user_id)` row and stitches in the immutable
+  `accounts.user_name`;
+- `NotificationPublisher` adapter that translates each
+  `DiplomailNotification` into a `notification.Intent` and routes it
+  through `*notification.Service.Submit`.

backend/internal/diplomail/admin_send.go

@@ -0,0 +1,615 @@
+package diplomail
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// SendAdminPersonal persists an admin-kind message addressed to a
+// single recipient and fan-outs the push event. The HTTP layer is
+// responsible for the owner-vs-admin authorisation decision; this
+// function trusts the caller designation it receives.
+//
+// The recipient may be in any membership status, so the lookup goes
+// through MembershipLookup.GetMembershipAnyStatus. This lets the
+// owner / admin reach a kicked player to explain the kick or follow
+// up after a removal.
+func (s *Service) SendAdminPersonal(ctx context.Context, in SendAdminPersonalInput) (Message, Recipient, error) {
+	subject, body, err := s.prepareContent(in.Subject, in.Body)
+	if err != nil {
+		return Message{}, Recipient{}, err
+	}
+	if err := validateCaller(in.CallerKind, in.CallerUserID, in.CallerUsername); err != nil {
+		return Message{}, Recipient{}, err
+	}
+
+	recipient, err := s.deps.Memberships.GetMembershipAnyStatus(ctx, in.GameID, in.RecipientUserID)
+	if err != nil {
+		if errors.Is(err, ErrNotFound) {
+			return Message{}, Recipient{}, fmt.Errorf("%w: recipient is not a member of the game", ErrForbidden)
+		}
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: load admin recipient: %w", err)
+	}
+
+	msgInsert, err := s.buildAdminMessageInsert(in.CallerKind, in.CallerUserID, in.CallerUsername,
+		recipient.GameID, recipient.GameName, subject, body, in.SenderIP, BroadcastScopeSingle)
+	if err != nil {
+		return Message{}, Recipient{}, err
+	}
+	rcptInsert := buildRecipientInsert(msgInsert.MessageID, recipient, msgInsert.BodyLang, s.nowUTC())
+
+	msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, []RecipientInsert{rcptInsert})
+	if err != nil {
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: send admin personal: %w", err)
+	}
+	if len(recipients) != 1 {
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: send admin personal: unexpected recipient count %d", len(recipients))
+	}
+
+	if recipients[0].AvailableAt != nil { s.publishMessageReceived(ctx, msg, recipients[0]) }
+	return msg, recipients[0], nil
+}
+
+// SendAdminBroadcast persists an admin-kind broadcast addressed to
+// every member matching `RecipientScope`, then emits one push event
+// per recipient. The caller's own membership row, when present, is
+// excluded from the recipient list — broadcasters do not get a copy
+// of their own message.
+func (s *Service) SendAdminBroadcast(ctx context.Context, in SendAdminBroadcastInput) (Message, []Recipient, error) {
+	subject, body, err := s.prepareContent(in.Subject, in.Body)
+	if err != nil {
+		return Message{}, nil, err
+	}
+	if err := validateCaller(in.CallerKind, in.CallerUserID, in.CallerUsername); err != nil {
+		return Message{}, nil, err
+	}
+	scope, err := normaliseScope(in.RecipientScope)
+	if err != nil {
+		return Message{}, nil, err
+	}
+
+	members, err := s.deps.Memberships.ListMembers(ctx, in.GameID, scope)
+	if err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail: list members for broadcast: %w", err)
+	}
+	members = filterOutCaller(members, in.CallerUserID)
+	if len(members) == 0 {
+		return Message{}, nil, fmt.Errorf("%w: no recipients for broadcast", ErrInvalidInput)
+	}
+
+	gameName := members[0].GameName
+	msgInsert, err := s.buildAdminMessageInsert(in.CallerKind, in.CallerUserID, in.CallerUsername,
+		in.GameID, gameName, subject, body, in.SenderIP, BroadcastScopeGameBroadcast)
+	if err != nil {
+		return Message{}, nil, err
+	}
+	rcptInserts := make([]RecipientInsert, 0, len(members))
+	for _, m := range members {
+		rcptInserts = append(rcptInserts, buildRecipientInsert(msgInsert.MessageID, m, msgInsert.BodyLang, s.nowUTC()))
+	}
+
+	msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, rcptInserts)
+	if err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail: send admin broadcast: %w", err)
+	}
+	for _, r := range recipients {
+		if r.AvailableAt != nil { s.publishMessageReceived(ctx, msg, r) }
+	}
+	return msg, recipients, nil
+}
+
+// SendPlayerBroadcast persists a paid-tier player broadcast and
+// fans out the push event to every other active member of the game.
+// The send is `kind="personal"`, `sender_kind="player"`,
+// `broadcast_scope="game_broadcast"` — recipients reply to it as if
+// it were a single-recipient personal send, and the reply targets
+// only the broadcaster. The caller's entitlement tier is checked
+// against `EntitlementReader`; free-tier callers are rejected with
+// ErrForbidden.
+func (s *Service) SendPlayerBroadcast(ctx context.Context, in SendPlayerBroadcastInput) (Message, []Recipient, error) {
+	subject, body, err := s.prepareContent(in.Subject, in.Body)
+	if err != nil {
+		return Message{}, nil, err
+	}
+	if s.deps.Entitlements == nil {
+		return Message{}, nil, fmt.Errorf("%w: entitlement reader is not wired", ErrForbidden)
+	}
+	paid, err := s.deps.Entitlements.IsPaidTier(ctx, in.SenderUserID)
+	if err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail: entitlement lookup: %w", err)
+	}
+	if !paid {
+		return Message{}, nil, fmt.Errorf("%w: in-game broadcast requires a paid tier", ErrForbidden)
+	}
+
+	sender, err := s.deps.Memberships.GetActiveMembership(ctx, in.GameID, in.SenderUserID)
+	if err != nil {
+		if errors.Is(err, ErrNotFound) {
+			return Message{}, nil, fmt.Errorf("%w: sender is not an active member of the game", ErrForbidden)
+		}
+		return Message{}, nil, fmt.Errorf("diplomail: load sender membership: %w", err)
+	}
+
+	members, err := s.deps.Memberships.ListMembers(ctx, in.GameID, RecipientScopeActive)
+	if err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail: list active members: %w", err)
+	}
+	callerID := in.SenderUserID
+	members = filterOutCaller(members, &callerID)
+	if len(members) == 0 {
+		return Message{}, nil, fmt.Errorf("%w: no other active members in this game", ErrInvalidInput)
+	}
+
+	username := sender.UserName
+	msgInsert := MessageInsert{
+		MessageID:      uuid.New(),
+		GameID:         in.GameID,
+		GameName:       sender.GameName,
+		Kind:           KindPersonal,
+		SenderKind:     SenderKindPlayer,
+		SenderUserID:   &callerID,
+		SenderUsername: &username,
+		SenderIP:       in.SenderIP,
+		Subject:        subject,
+		Body:           body,
+		BodyLang:       s.deps.Detector.Detect(body),
+		BroadcastScope: BroadcastScopeGameBroadcast,
+	}
+	rcptInserts := make([]RecipientInsert, 0, len(members))
+	for _, m := range members {
+		rcptInserts = append(rcptInserts, buildRecipientInsert(msgInsert.MessageID, m, msgInsert.BodyLang, s.nowUTC()))
+	}
+	msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, rcptInserts)
+	if err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail: send player broadcast: %w", err)
+	}
+	for _, r := range recipients {
+		if r.AvailableAt != nil { s.publishMessageReceived(ctx, msg, r) }
+	}
+	return msg, recipients, nil
+}
+
+// SendAdminMultiGameBroadcast emits one admin-kind message per game
+// resolved from the input scope and fans out the push events. A
+// recipient who plays in multiple addressed games receives one
+// independently-deletable inbox entry per game; this avoids cross-
+// game leakage of admin context and keeps the per-game unread badge
+// honest.
+func (s *Service) SendAdminMultiGameBroadcast(ctx context.Context, in SendMultiGameBroadcastInput) ([]Message, int, error) {
+	subject, body, err := s.prepareContent(in.Subject, in.Body)
+	if err != nil {
+		return nil, 0, err
+	}
+	if err := validateCaller(CallerKindAdmin, nil, in.CallerUsername); err != nil {
+		return nil, 0, err
+	}
+	scope, err := normaliseScope(in.RecipientScope)
+	if err != nil {
+		return nil, 0, err
+	}
+	if s.deps.Games == nil {
+		return nil, 0, fmt.Errorf("%w: game lookup is not wired", ErrInvalidInput)
+	}
+	games, err := s.resolveMultiGameTargets(ctx, in)
+	if err != nil {
+		return nil, 0, err
+	}
+	if len(games) == 0 {
+		return nil, 0, fmt.Errorf("%w: no games match the broadcast scope", ErrInvalidInput)
+	}
+
+	totalRecipients := 0
+	out := make([]Message, 0, len(games))
+	for _, game := range games {
+		members, err := s.deps.Memberships.ListMembers(ctx, game.GameID, scope)
+		if err != nil {
+			return nil, 0, fmt.Errorf("diplomail: list members for %s: %w", game.GameID, err)
+		}
+		if len(members) == 0 {
+			s.deps.Logger.Debug("multi-game broadcast skips empty game",
+				zap.String("game_id", game.GameID.String()),
+				zap.String("scope", scope))
+			continue
+		}
+		msgInsert, err := s.buildAdminMessageInsert(CallerKindAdmin, nil, in.CallerUsername,
+			game.GameID, game.GameName, subject, body, in.SenderIP, BroadcastScopeMultiGameBroadcast)
+		if err != nil {
+			return nil, 0, err
+		}
+		rcptInserts := make([]RecipientInsert, 0, len(members))
+		for _, m := range members {
+			rcptInserts = append(rcptInserts, buildRecipientInsert(msgInsert.MessageID, m, msgInsert.BodyLang, s.nowUTC()))
+		}
+		msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, rcptInserts)
+		if err != nil {
+			return nil, 0, fmt.Errorf("diplomail: insert multi-game broadcast for %s: %w", game.GameID, err)
+		}
+		for _, r := range recipients {
+			if r.AvailableAt != nil { s.publishMessageReceived(ctx, msg, r) }
+		}
+		out = append(out, msg)
+		totalRecipients += len(recipients)
+	}
+	return out, totalRecipients, nil
+}
+
+func (s *Service) resolveMultiGameTargets(ctx context.Context, in SendMultiGameBroadcastInput) ([]GameSnapshot, error) {
+	switch in.Scope {
+	case MultiGameScopeAllRunning:
+		games, err := s.deps.Games.ListRunningGames(ctx)
+		if err != nil {
+			return nil, fmt.Errorf("diplomail: list running games: %w", err)
+		}
+		return games, nil
+	case MultiGameScopeSelected, "":
+		if len(in.GameIDs) == 0 {
+			return nil, fmt.Errorf("%w: selected scope requires game_ids", ErrInvalidInput)
+		}
+		out := make([]GameSnapshot, 0, len(in.GameIDs))
+		for _, id := range in.GameIDs {
+			game, err := s.deps.Games.GetGame(ctx, id)
+			if err != nil {
+				if errors.Is(err, ErrNotFound) {
+					return nil, fmt.Errorf("%w: game %s not found", ErrInvalidInput, id)
+				}
+				return nil, fmt.Errorf("diplomail: load game %s: %w", id, err)
+			}
+			out = append(out, game)
+		}
+		return out, nil
+	default:
+		return nil, fmt.Errorf("%w: unknown multi-game scope %q", ErrInvalidInput, in.Scope)
+	}
+}
+
+// BulkCleanup deletes every diplomail_messages row tied to games that
+// finished more than `OlderThanYears` years ago. Returns the affected
+// game ids and the count of removed messages. The minimum allowed
+// value is 1 year — finer-grained pruning would risk wiping live
+// arbitration evidence.
+func (s *Service) BulkCleanup(ctx context.Context, in BulkCleanupInput) (CleanupResult, error) {
+	if in.OlderThanYears < 1 {
+		return CleanupResult{}, fmt.Errorf("%w: older_than_years must be >= 1", ErrInvalidInput)
+	}
+	if s.deps.Games == nil {
+		return CleanupResult{}, fmt.Errorf("%w: game lookup is not wired", ErrInvalidInput)
+	}
+	cutoff := s.nowUTC().AddDate(-in.OlderThanYears, 0, 0)
+	games, err := s.deps.Games.ListFinishedGamesBefore(ctx, cutoff)
+	if err != nil {
+		return CleanupResult{}, fmt.Errorf("diplomail: list finished games: %w", err)
+	}
+	if len(games) == 0 {
+		return CleanupResult{}, nil
+	}
+	gameIDs := make([]uuid.UUID, 0, len(games))
+	for _, g := range games {
+		gameIDs = append(gameIDs, g.GameID)
+	}
+	deleted, err := s.deps.Store.DeleteMessagesForGames(ctx, gameIDs)
+	if err != nil {
+		return CleanupResult{}, fmt.Errorf("diplomail: bulk delete: %w", err)
+	}
+	return CleanupResult{GameIDs: gameIDs, MessagesDeleted: deleted}, nil
+}
+
+// ListMessagesForAdmin returns a paginated, optionally-filtered view
+// of every persisted message. Used by the admin observability
+// endpoint to inspect what has been sent and trace abuse reports.
+func (s *Service) ListMessagesForAdmin(ctx context.Context, filter AdminMessageListing) (AdminMessagePage, error) {
+	rows, total, err := s.deps.Store.ListMessagesForAdmin(ctx, filter)
+	if err != nil {
+		return AdminMessagePage{}, err
+	}
+	page := filter.Page
+	if page < 1 {
+		page = 1
+	}
+	pageSize := filter.PageSize
+	if pageSize < 1 {
+		pageSize = 50
+	}
+	return AdminMessagePage{
+		Items:    rows,
+		Total:    total,
+		Page:     page,
+		PageSize: pageSize,
+	}, nil
+}
+
+// PublishLifecycle persists a system-kind message in response to a
+// lobby lifecycle transition and fan-outs push events to the
+// affected recipients. Game-scoped transitions (`game.paused`,
+// `game.cancelled`) reach every active member; membership-scoped
+// transitions (`membership.removed`, `membership.blocked`) reach the
+// kicked player only. Failures inside the function are logged at
+// Warn level — lifecycle hooks must not block the lobby state
+// machine on a downstream mail failure.
+func (s *Service) PublishLifecycle(ctx context.Context, ev LifecycleEvent) error {
+	switch ev.Kind {
+	case LifecycleKindGamePaused, LifecycleKindGameCancelled:
+		return s.publishGameLifecycle(ctx, ev)
+	case LifecycleKindMembershipRemoved, LifecycleKindMembershipBlocked:
+		return s.publishMembershipLifecycle(ctx, ev)
+	default:
+		return fmt.Errorf("%w: unknown lifecycle kind %q", ErrInvalidInput, ev.Kind)
+	}
+}
+
+func (s *Service) publishGameLifecycle(ctx context.Context, ev LifecycleEvent) error {
+	members, err := s.deps.Memberships.ListMembers(ctx, ev.GameID, RecipientScopeActive)
+	if err != nil {
+		return fmt.Errorf("diplomail lifecycle: list members for %s: %w", ev.GameID, err)
+	}
+	if len(members) == 0 {
+		s.deps.Logger.Debug("lifecycle skip: no active members",
+			zap.String("game_id", ev.GameID.String()),
+			zap.String("kind", ev.Kind))
+		return nil
+	}
+	gameName := members[0].GameName
+	subject, body := renderGameLifecycle(ev.Kind, gameName, ev.Actor, ev.Reason)
+
+	msgInsert, err := s.buildAdminMessageInsert(CallerKindSystem, nil, "",
+		ev.GameID, gameName, subject, body, "", BroadcastScopeGameBroadcast)
+	if err != nil {
+		return err
+	}
+	rcptInserts := make([]RecipientInsert, 0, len(members))
+	for _, m := range members {
+		rcptInserts = append(rcptInserts, buildRecipientInsert(msgInsert.MessageID, m, msgInsert.BodyLang, s.nowUTC()))
+	}
+	msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, rcptInserts)
+	if err != nil {
+		return fmt.Errorf("diplomail lifecycle: insert %s system mail: %w", ev.Kind, err)
+	}
+	for _, r := range recipients {
+		if r.AvailableAt != nil { s.publishMessageReceived(ctx, msg, r) }
+	}
+	return nil
+}
+
+func (s *Service) publishMembershipLifecycle(ctx context.Context, ev LifecycleEvent) error {
+	if ev.TargetUser == nil {
+		return fmt.Errorf("%w: membership lifecycle requires TargetUser", ErrInvalidInput)
+	}
+	target, err := s.deps.Memberships.GetMembershipAnyStatus(ctx, ev.GameID, *ev.TargetUser)
+	if err != nil {
+		return fmt.Errorf("diplomail lifecycle: load target membership: %w", err)
+	}
+	subject, body := renderMembershipLifecycle(ev.Kind, target.GameName, ev.Actor, ev.Reason)
+
+	msgInsert, err := s.buildAdminMessageInsert(CallerKindSystem, nil, "",
+		ev.GameID, target.GameName, subject, body, "", BroadcastScopeSingle)
+	if err != nil {
+		return err
+	}
+	rcptInsert := buildRecipientInsert(msgInsert.MessageID, target, msgInsert.BodyLang, s.nowUTC())
+	msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, []RecipientInsert{rcptInsert})
+	if err != nil {
+		return fmt.Errorf("diplomail lifecycle: insert %s system mail: %w", ev.Kind, err)
+	}
+	if len(recipients) == 1 && recipients[0].AvailableAt != nil {
+		s.publishMessageReceived(ctx, msg, recipients[0])
+	}
+	return nil
+}
+
+// prepareContent normalises subject and body the same way SendPersonal
+// does. Factored out so admin and lifecycle paths share the
+// length-and-utf8 validation rules.
+func (s *Service) prepareContent(subject, body string) (string, string, error) {
+	subj := strings.TrimRight(subject, " \t")
+	bod := strings.TrimRight(body, " \t\n")
+	if err := s.validateContent(subj, bod); err != nil {
+		return "", "", err
+	}
+	return subj, bod, nil
+}
+
+// buildAdminMessageInsert encapsulates the message-row construction
+// for every admin-kind send. The CHECK constraint maps sender
+// shapes:
+//
+//	sender_kind='player'  → CallerKind owner; sender_user_id set
+//	sender_kind='admin'   → CallerKind admin; sender_user_id nil
+//	sender_kind='system'  → CallerKind system; sender_username nil
+func (s *Service) buildAdminMessageInsert(callerKind string, callerUserID *uuid.UUID, callerUsername string,
+	gameID uuid.UUID, gameName, subject, body, senderIP, scope string) (MessageInsert, error) {
+	out := MessageInsert{
+		MessageID:      uuid.New(),
+		GameID:         gameID,
+		GameName:       gameName,
+		Kind:           KindAdmin,
+		SenderIP:       senderIP,
+		Subject:        subject,
+		Body:           body,
+		BodyLang:       s.deps.Detector.Detect(body),
+		BroadcastScope: scope,
+	}
+	switch callerKind {
+	case CallerKindOwner:
+		if callerUserID == nil {
+			return MessageInsert{}, fmt.Errorf("%w: owner send requires caller user id", ErrInvalidInput)
+		}
+		uid := *callerUserID
+		uname := callerUsername
+		out.SenderKind = SenderKindPlayer
+		out.SenderUserID = &uid
+		out.SenderUsername = &uname
+	case CallerKindAdmin:
+		uname := callerUsername
+		out.SenderKind = SenderKindAdmin
+		out.SenderUsername = &uname
+	case CallerKindSystem:
+		out.SenderKind = SenderKindSystem
+	default:
+		return MessageInsert{}, fmt.Errorf("%w: unknown caller kind %q", ErrInvalidInput, callerKind)
+	}
+	return out, nil
+}
+
+// buildRecipientInsert turns a MemberSnapshot into a RecipientInsert.
+// The race-name snapshot is nullable so a kicked player with no race
+// name on file is still addressable.
+//
+// `bodyLang` is the detected language of the message body. When the
+// recipient's preferred_language matches body_lang (or body_lang is
+// undetermined), the function fills AvailableAt with `now` so the
+// recipient row is materialised already-delivered; otherwise
+// AvailableAt stays nil and the translation worker takes over.
+func buildRecipientInsert(messageID uuid.UUID, m MemberSnapshot, bodyLang string, now time.Time) RecipientInsert {
+	in := RecipientInsert{
+		RecipientID:                uuid.New(),
+		MessageID:                  messageID,
+		GameID:                     m.GameID,
+		UserID:                     m.UserID,
+		RecipientUserName:          m.UserName,
+		RecipientPreferredLanguage: normaliseLang(m.PreferredLanguage),
+	}
+	if m.RaceName != "" {
+		race := m.RaceName
+		in.RecipientRaceName = &race
+	}
+	if needsTranslation(bodyLang, in.RecipientPreferredLanguage) {
+		// AvailableAt left nil → worker will deliver after the
+		// translation cache is materialised (or after fallback).
+	} else {
+		t := now.UTC()
+		in.AvailableAt = &t
+	}
+	return in
+}
+
+// needsTranslation reports whether a recipient with preferredLang
+// needs to wait for a translated rendering before the message is
+// considered delivered. Undetermined body language and empty
+// recipient preferences are short-circuited to "no translation
+// needed" so we never block delivery on something the detector
+// could not label.
+func needsTranslation(bodyLang, preferredLang string) bool {
+	bodyLang = normaliseLang(bodyLang)
+	preferredLang = normaliseLang(preferredLang)
+	if bodyLang == "" || bodyLang == LangUndetermined {
+		return false
+	}
+	if preferredLang == "" || preferredLang == LangUndetermined {
+		return false
+	}
+	return bodyLang != preferredLang
+}
+
+// normaliseLang strips any region subtag and lowercases the result so
+// `en-US` and `EN` both collapse to `en`. The diplomail layer uses
+// ISO 639-1 codes; whatlanggo and LibreTranslate share that
+// vocabulary.
+func normaliseLang(tag string) string {
+	tag = strings.TrimSpace(tag)
+	if tag == "" {
+		return ""
+	}
+	if i := strings.IndexAny(tag, "-_"); i > 0 {
+		tag = tag[:i]
+	}
+	return strings.ToLower(tag)
+}
+
+func validateCaller(callerKind string, callerUserID *uuid.UUID, callerUsername string) error {
+	switch callerKind {
+	case CallerKindOwner:
+		if callerUserID == nil {
+			return fmt.Errorf("%w: owner send requires caller_user_id", ErrInvalidInput)
+		}
+		if callerUsername == "" {
+			return fmt.Errorf("%w: owner send requires caller_username", ErrInvalidInput)
+		}
+	case CallerKindAdmin:
+		if callerUsername == "" {
+			return fmt.Errorf("%w: admin send requires caller_username", ErrInvalidInput)
+		}
+	case CallerKindSystem:
+		// no extra checks
+	default:
+		return fmt.Errorf("%w: unknown caller_kind %q", ErrInvalidInput, callerKind)
+	}
+	return nil
+}
+
+func normaliseScope(scope string) (string, error) {
+	switch scope {
+	case "", RecipientScopeActive:
+		return RecipientScopeActive, nil
+	case RecipientScopeActiveAndRemoved, RecipientScopeAllMembers:
+		return scope, nil
+	default:
+		return "", fmt.Errorf("%w: unknown recipient scope %q", ErrInvalidInput, scope)
+	}
+}
+
+func filterOutCaller(members []MemberSnapshot, callerUserID *uuid.UUID) []MemberSnapshot {
+	if callerUserID == nil {
+		return members
+	}
+	out := make([]MemberSnapshot, 0, len(members))
+	for _, m := range members {
+		if m.UserID == *callerUserID {
+			continue
+		}
+		out = append(out, m)
+	}
+	return out
+}
+
+// renderGameLifecycle returns the (subject, body) pair persisted for
+// the `game.paused` / `game.cancelled` system message. Bodies are in
+// English; Stage D will translate them on demand into each
+// recipient's preferred_language and cache the result.
+func renderGameLifecycle(kind, gameName, actor, reason string) (string, string) {
+	actor = strings.TrimSpace(actor)
+	if actor == "" {
+		actor = "the system"
+	}
+	reasonTail := ""
+	if r := strings.TrimSpace(reason); r != "" {
+		reasonTail = " Reason: " + r + "."
+	}
+	switch kind {
+	case LifecycleKindGamePaused:
+		return "Game paused",
+			fmt.Sprintf("The game %q has been paused by %s.%s", gameName, actor, reasonTail)
+	case LifecycleKindGameCancelled:
+		return "Game cancelled",
+			fmt.Sprintf("The game %q has been cancelled by %s.%s", gameName, actor, reasonTail)
+	}
+	return "Game lifecycle update",
+		fmt.Sprintf("The game %q has changed state.%s", gameName, reasonTail)
+}
+
+// renderMembershipLifecycle returns the (subject, body) pair persisted
+// for the `membership.removed` / `membership.blocked` system message.
+func renderMembershipLifecycle(kind, gameName, actor, reason string) (string, string) {
+	actor = strings.TrimSpace(actor)
+	if actor == "" {
+		actor = "the system"
+	}
+	reasonTail := ""
+	if r := strings.TrimSpace(reason); r != "" {
+		reasonTail = " Reason: " + r + "."
+	}
+	switch kind {
+	case LifecycleKindMembershipRemoved:
+		return "Membership removed",
+			fmt.Sprintf("Your membership in %q has been removed by %s.%s", gameName, actor, reasonTail)
+	case LifecycleKindMembershipBlocked:
+		return "Membership blocked",
+			fmt.Sprintf("Your membership in %q has been blocked by %s.%s", gameName, actor, reasonTail)
+	}
+	return "Membership update",
+		fmt.Sprintf("Your membership in %q has changed.%s", gameName, reasonTail)
+}

backend/internal/diplomail/deps.go

@@ -0,0 +1,181 @@
+package diplomail
+
+import (
+	"context"
+	"time"
+
+	"galaxy/backend/internal/config"
+	"galaxy/backend/internal/diplomail/detector"
+	"galaxy/backend/internal/diplomail/translator"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// Deps aggregates every collaborator the diplomail Service depends on.
+//
+// Store and Memberships are required. Logger and Now default to
+// zap.NewNop / time.Now when nil. Notification falls back to a no-op
+// publisher so unit tests can construct a Service with only the
+// required collaborators populated. Entitlements and Games are
+// optional — they are used by Stage C surfaces (paid-tier player
+// broadcast, multi-game admin broadcast, bulk cleanup). Wiring may
+// pass nil for tests that do not exercise those paths.
+type Deps struct {
+	Store        *Store
+	Memberships  MembershipLookup
+	Notification NotificationPublisher
+	Entitlements EntitlementReader
+	Games        GameLookup
+	Detector     detector.LanguageDetector
+	Translator   translator.Translator
+	Config       config.DiplomailConfig
+	Logger       *zap.Logger
+	Now          func() time.Time
+}
+
+// EntitlementReader is the read-only surface diplomail uses to gate
+// the paid-tier player broadcast. The canonical implementation in
+// `cmd/backend/main` reads
+// `*user.Service.GetEntitlementSnapshot(userID).IsPaid`.
+type EntitlementReader interface {
+	IsPaidTier(ctx context.Context, userID uuid.UUID) (bool, error)
+}
+
+// GameLookup exposes the slim view of `games` the multi-game admin
+// broadcast and bulk-cleanup paths consume. The canonical
+// implementation walks the lobby cache plus an explicit store call
+// for finished-game pruning.
+type GameLookup interface {
+	// ListRunningGames returns every game whose `status` is one of
+	// the still-active values (running, paused, starting, …). The
+	// admin `all_running` broadcast scope iterates over the result.
+	ListRunningGames(ctx context.Context) ([]GameSnapshot, error)
+
+	// ListFinishedGamesBefore returns every game whose `finished_at`
+	// is older than `cutoff`. The bulk-purge admin endpoint reads
+	// this to compose the cascade-delete IN list.
+	ListFinishedGamesBefore(ctx context.Context, cutoff time.Time) ([]GameSnapshot, error)
+
+	// GetGame returns one game snapshot identified by id, or
+	// ErrNotFound. Used by the multi-game broadcast to verify the
+	// caller-supplied id list before enqueuing fan-out work.
+	GetGame(ctx context.Context, gameID uuid.UUID) (GameSnapshot, error)
+}
+
+// GameSnapshot is the trim view of `games` consumed by the multi-game
+// admin broadcast and the cleanup paths. The struct intentionally
+// avoids the full `lobby.GameRecord` so the diplomail package stays
+// decoupled from the lobby domain.
+type GameSnapshot struct {
+	GameID      uuid.UUID
+	GameName    string
+	Status      string
+	FinishedAt  *time.Time
+}
+
+// ActiveMembership is the slim view of a single (user, game) roster
+// row the diplomail package needs at send time: it confirms the
+// participant is active in the game and captures the snapshot fields
+// (`game_name`, `user_name`, `race_name`, `preferred_language`) that
+// we persist on each new message / recipient row.
+type ActiveMembership struct {
+	UserID            uuid.UUID
+	GameID            uuid.UUID
+	GameName          string
+	UserName          string
+	RaceName          string
+	PreferredLanguage string
+}
+
+// MembershipLookup is the read-only surface diplomail uses to verify
+// "is this user an active member of this game" and to snapshot the
+// roster metadata. The canonical implementation in `cmd/backend/main`
+// adapts the `*lobby.Service` membership cache to this interface.
+//
+// GetActiveMembership returns ErrNotFound (the diplomail sentinel)
+// when the user is not an active member of the game; the service
+// boundary maps that to 403 forbidden.
+//
+// GetMembershipAnyStatus returns the same shape regardless of
+// membership status (`active`, `removed`, `blocked`). Used by the
+// inbox read path to check whether a kicked recipient still belongs
+// to the game's roster; ErrNotFound is surfaced when the user has
+// never been a member.
+//
+// ListMembers returns every roster row matching scope, in stable
+// order. Scope values are `active`, `active_and_removed`, and
+// `all_members` (the spec calls these out by name). Used by the
+// broadcast composition step in admin / owner sends.
+type MembershipLookup interface {
+	GetActiveMembership(ctx context.Context, gameID, userID uuid.UUID) (ActiveMembership, error)
+	GetMembershipAnyStatus(ctx context.Context, gameID, userID uuid.UUID) (MemberSnapshot, error)
+	ListMembers(ctx context.Context, gameID uuid.UUID, scope string) ([]MemberSnapshot, error)
+}
+
+// Recipient scope values accepted by ListMembers and by the
+// `recipients` request field on admin / owner broadcasts.
+const (
+	RecipientScopeActive            = "active"
+	RecipientScopeActiveAndRemoved  = "active_and_removed"
+	RecipientScopeAllMembers        = "all_members"
+)
+
+// MemberSnapshot is the slim view of a membership row that survives
+// all three status values. RaceName is the immutable string captured
+// at registration time; an empty value is legal for rare cases where
+// the row was inserted without one. PreferredLanguage is included so
+// the broadcast and lifecycle paths can decide whether the recipient
+// needs to wait for a translation before delivery.
+type MemberSnapshot struct {
+	UserID            uuid.UUID
+	GameID            uuid.UUID
+	GameName          string
+	UserName          string
+	RaceName          string
+	PreferredLanguage string
+	Status            string
+}
+
+// NotificationPublisher is the outbound surface diplomail uses to
+// emit the `diplomail.message.received` push event. The canonical
+// implementation in `cmd/backend/main` adapts the notification.Service
+// the same way it adapts `lobby.NotificationPublisher`; tests pass
+// the no-op publisher below to avoid wiring the dispatcher.
+type NotificationPublisher interface {
+	PublishDiplomailEvent(ctx context.Context, ev DiplomailNotification) error
+}
+
+// DiplomailNotification is the open shape carried by a per-recipient
+// push intent. The struct lives in the diplomail package so the
+// producer vocabulary stays here; the publisher adapter translates it
+// into a `notification.Intent` at the wiring boundary.
+type DiplomailNotification struct {
+	Kind           string
+	IdempotencyKey string
+	Recipient      uuid.UUID
+	Payload        map[string]any
+}
+
+// NewNoopNotificationPublisher returns a publisher that logs every
+// call at debug level and returns nil. Used by unit tests and as the
+// fallback inside NewService when callers leave Deps.Notification nil.
+func NewNoopNotificationPublisher(logger *zap.Logger) NotificationPublisher {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	return &noopNotificationPublisher{logger: logger.Named("diplomail.notify.noop")}
+}
+
+type noopNotificationPublisher struct {
+	logger *zap.Logger
+}
+
+func (p *noopNotificationPublisher) PublishDiplomailEvent(_ context.Context, ev DiplomailNotification) error {
+	p.logger.Debug("noop notification",
+		zap.String("kind", ev.Kind),
+		zap.String("idempotency_key", ev.IdempotencyKey),
+		zap.String("recipient", ev.Recipient.String()),
+	)
+	return nil
+}

backend/internal/diplomail/detector/detector.go

@@ -0,0 +1,79 @@
+// Package detector wraps the body-language detection used by the
+// diplomail subsystem. The package exposes a narrow `LanguageDetector`
+// interface so the implementation can be swapped without touching the
+// callers; the default backed-by-whatlanggo detector handles 84
+// natural languages and ships with the embedded statistical profiles.
+//
+// Detection happens only on the body. Subjects are short and
+// frequently template-like ("Re: ..."), so detecting on them adds
+// noise. The diplomail Service feeds the body, captures the BCP 47
+// tag returned here, and stores it in `diplomail_messages.body_lang`.
+package detector
+
+import (
+	"strings"
+	"unicode/utf8"
+
+	"github.com/abadojack/whatlanggo"
+)
+
+// Undetermined is the BCP 47 placeholder stored when detection cannot
+// confidently identify a language (empty body, too-short body, mixed
+// scripts the detector refuses to bet on).
+const Undetermined = "und"
+
+// LanguageDetector is the read-only surface diplomail consumes when
+// it needs to label a message body. Detect must never panic and
+// must never return an error: detection failure simply yields
+// `Undetermined`.
+type LanguageDetector interface {
+	Detect(body string) string
+}
+
+// New returns the package-default detector backed by `whatlanggo`.
+// The instance is safe for concurrent use; whatlanggo's `Detect`
+// reads the embedded profiles without state mutation. Callers that
+// want a fixed allow-list can build their own implementation around
+// the same interface.
+func New() LanguageDetector {
+	return &whatlangDetector{}
+}
+
+type whatlangDetector struct{}
+
+// minRunes is the lower bound on body length below which whatlanggo
+// can flip between near-synonyms; for shorter bodies we return
+// `Undetermined` and let the noop translator skip the slot. The
+// value matches whatlanggo's documented "stable above ~25 runes"
+// guidance.
+const minRunes = 25
+
+// Detect returns the BCP 47 tag for body, or `Undetermined` when the
+// body is empty / too short / whatlanggo refuses to label it. The
+// trim is applied so leading whitespace does not bias the script
+// detector toward Latin. We deliberately do not gate on
+// `info.IsReliable()` because the gate is too conservative for the
+// short sentences typical of in-game mail; a misclassification only
+// hurts the translation cache key, never correctness.
+func (d *whatlangDetector) Detect(body string) string {
+	body = strings.TrimSpace(body)
+	if body == "" {
+		return Undetermined
+	}
+	if utf8.RuneCountInString(body) < minRunes {
+		return Undetermined
+	}
+	info := whatlanggo.Detect(body)
+	tag := info.Lang.Iso6391()
+	if tag == "" {
+		return Undetermined
+	}
+	return tag
+}
+
+// NoopDetector returns the placeholder unconditionally. Used by
+// tests and by Stage A code paths that predate the real detector.
+type NoopDetector struct{}
+
+// Detect always returns `Undetermined` regardless of input.
+func (NoopDetector) Detect(string) string { return Undetermined }

backend/internal/diplomail/detector/detector_test.go

@@ -0,0 +1,49 @@
+package detector
+
+import "testing"
+
+func TestDetectKnownLanguages(t *testing.T) {
+	t.Parallel()
+	d := New()
+	cases := []struct {
+		name string
+		text string
+		want string
+	}{
+		{
+			name: "english paragraph",
+			text: "The trade agreement should be signed before the next turn. " +
+				"I expect a written response by the time the engine generates the next report.",
+			want: "en",
+		},
+		{
+			name: "russian paragraph",
+			text: "Привет! Я предлагаю заключить дипломатическое соглашение и провести " +
+				"совместную операцию по освоению гиперпространственных маршрутов. " +
+				"Жду твоего письменного ответа до конца следующего хода игры, " +
+				"чтобы мы успели согласовать детали и подписать договор вовремя.",
+			want: "ru",
+		},
+	}
+	for _, tc := range cases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			got := d.Detect(tc.text)
+			if got != tc.want {
+				t.Fatalf("Detect = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestDetectShortOrEmpty(t *testing.T) {
+	t.Parallel()
+	d := New()
+	short := []string{"", "hi", "    "}
+	for _, s := range short {
+		if got := d.Detect(s); got != Undetermined {
+			t.Errorf("Detect(%q) = %q, want %q", s, got, Undetermined)
+		}
+	}
+}

backend/internal/diplomail/diplomail.go

@@ -0,0 +1,135 @@
+// Package diplomail owns the diplomatic-mail subsystem of the Galaxy
+// backend service. Messages live in the lobby-side domain (their
+// storage and lifecycle are tied to a game), but they are surfaced
+// in-game: lobby exposes only an unread-count badge per game while the
+// in-game mail view reads and writes through this package.
+//
+// Stage A implements the personal single-recipient subset:
+//
+//   - send/read/mark-read/soft-delete handlers for a player addressing
+//     one other active member of the game;
+//   - a push event (`diplomail.message.received`) materialised through
+//     the existing notification pipeline so the recipient gets a live
+//     toast when online;
+//   - an unread-counts endpoint that drives the lobby badge.
+//
+// Later stages add admin/owner/system mail, lifecycle hooks, paid-tier
+// player broadcasts, multi-game broadcasts, bulk purge, and the
+// language-detection / translation cache.
+package diplomail
+
+import (
+	"time"
+
+	"galaxy/backend/internal/config"
+	"galaxy/backend/internal/diplomail/detector"
+	"galaxy/backend/internal/diplomail/translator"
+
+	"go.uber.org/zap"
+)
+
+// Kind values stored verbatim in `diplomail_messages.kind`. The schema
+// CHECK constraint pins this to the closed set declared below.
+const (
+	// KindPersonal is a replyable player-to-player message. The
+	// sender is always a `sender_kind='player'`.
+	KindPersonal = "personal"
+
+	// KindAdmin is a non-replyable administrative notification.
+	// The sender is either a human admin (`sender_kind='admin'`)
+	// or the system itself (`sender_kind='system'`).
+	KindAdmin = "admin"
+)
+
+// Sender kind values stored verbatim in `diplomail_messages.sender_kind`.
+const (
+	// SenderKindPlayer marks the sender as an end-user account.
+	// `sender_user_id` and `sender_username` carry the player's id
+	// and immutable `accounts.user_name`.
+	SenderKindPlayer = "player"
+
+	// SenderKindAdmin marks the sender as a site administrator.
+	// `sender_username` carries `admin_accounts.username`.
+	SenderKindAdmin = "admin"
+
+	// SenderKindSystem marks the sender as the service itself
+	// (lifecycle hooks). Both id and username are NULL.
+	SenderKindSystem = "system"
+)
+
+// Broadcast scope values stored verbatim in
+// `diplomail_messages.broadcast_scope`. Stage A only emits `single`;
+// Stage B / C add `game_broadcast` and `multi_game_broadcast`.
+const (
+	BroadcastScopeSingle             = "single"
+	BroadcastScopeGameBroadcast      = "game_broadcast"
+	BroadcastScopeMultiGameBroadcast = "multi_game_broadcast"
+)
+
+// LangUndetermined is the BCP 47 placeholder stored in
+// `diplomail_messages.body_lang` when language detection has not yet
+// been performed or could not produce a result. Stage A writes this
+// value unconditionally; Stage D replaces it with the detected tag.
+const LangUndetermined = "und"
+
+// Service is the diplomatic-mail entry point. Every public method is
+// goroutine-safe; concurrency safety is delegated to Postgres for
+// persisted state.
+type Service struct {
+	deps Deps
+}
+
+// NewService constructs a Service from deps. Logger and Now are
+// defaulted; Store must be non-nil and Memberships must be non-nil
+// because every send path queries the active membership roster.
+func NewService(deps Deps) *Service {
+	if deps.Logger == nil {
+		deps.Logger = zap.NewNop()
+	}
+	deps.Logger = deps.Logger.Named("diplomail")
+	if deps.Now == nil {
+		deps.Now = time.Now
+	}
+	if deps.Notification == nil {
+		deps.Notification = NewNoopNotificationPublisher(deps.Logger)
+	}
+	if deps.Detector == nil {
+		deps.Detector = detector.NoopDetector{}
+	}
+	if deps.Translator == nil {
+		deps.Translator = translator.NewNoop()
+	}
+	if deps.Config.MaxBodyBytes <= 0 {
+		deps.Config.MaxBodyBytes = 4096
+	}
+	if deps.Config.MaxSubjectBytes < 0 {
+		deps.Config.MaxSubjectBytes = 256
+	}
+	return &Service{deps: deps}
+}
+
+// Config returns the service's runtime configuration. Tests and the
+// HTTP layer occasionally surface the limits to clients (the OpenAPI
+// schema documents them too).
+func (s *Service) Config() config.DiplomailConfig {
+	if s == nil {
+		return config.DiplomailConfig{}
+	}
+	return s.deps.Config
+}
+
+// Logger returns the package-named logger. Used by the optional async
+// worker and by tests asserting on log output.
+func (s *Service) Logger() *zap.Logger {
+	if s == nil {
+		return zap.NewNop()
+	}
+	return s.deps.Logger
+}
+
+// nowUTC returns the configured clock normalised to UTC. Matches the
+// convention used everywhere else in `backend` so persisted
+// timestamps compare cleanly regardless of host timezone.
+func (s *Service) nowUTC() time.Time {
+	return s.deps.Now().UTC()
+}

backend/internal/diplomail/errors.go

@@ -0,0 +1,32 @@
+package diplomail
+
+import "errors"
+
+// Sentinel errors surface common rejection reasons across the
+// diplomail package. Handlers map them to HTTP envelopes through
+// `respondDiplomailError` in `internal/server/handlers_user_mail.go`.
+//
+// Adding a new sentinel here is a deliberate API change: it appears in
+// the handler error map and may surface as a new wire `code` value.
+// Reuse the existing set when the behaviour overlaps.
+var (
+	// ErrInvalidInput reports request-level validation failures
+	// (empty body, body or subject over the configured byte limit,
+	// invalid UUID, non-UTF-8 bytes). Maps to 400 invalid_request.
+	ErrInvalidInput = errors.New("diplomail: invalid input")
+
+	// ErrNotFound reports that the requested message does not exist
+	// or is not visible to the caller. Maps to 404 not_found.
+	ErrNotFound = errors.New("diplomail: not found")
+
+	// ErrForbidden reports that the caller is authenticated but not
+	// authorised for the requested action (not an active member of
+	// the game; not a recipient of the message). Maps to 403
+	// forbidden.
+	ErrForbidden = errors.New("diplomail: forbidden")
+
+	// ErrConflict reports that the requested action conflicts with
+	// the current persisted state (e.g. soft-deleting a message
+	// that has not been marked read yet). Maps to 409 conflict.
+	ErrConflict = errors.New("diplomail: conflict")
+)

backend/internal/diplomail/service.go

@@ -0,0 +1,389 @@
+package diplomail
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// previewMaxRunes bounds the body excerpt embedded in the push event
+// so the gRPC payload stays small. The value matches the UI's
+// "two lines" tease and is intentionally not configurable — clients
+// drive their own truncation off the canonical fetch.
+const previewMaxRunes = 120
+
+// SendPersonal persists a single-recipient personal message and
+// fan-outs a `diplomail.message.received` push event to the
+// recipient. Validation rules:
+//
+//   - both sender and recipient must be active members of GameID;
+//   - the recipient must differ from the sender;
+//   - the body must be non-empty, valid UTF-8, and within the
+//     configured byte limit;
+//   - the subject must be valid UTF-8 and within the configured
+//     byte limit (zero is allowed).
+//
+// On any rule violation the function returns ErrInvalidInput or
+// ErrForbidden; the inserted Message is never persisted in those
+// cases.
+func (s *Service) SendPersonal(ctx context.Context, in SendPersonalInput) (Message, Recipient, error) {
+	if in.SenderUserID == in.RecipientUserID {
+		return Message{}, Recipient{}, fmt.Errorf("%w: cannot send mail to yourself", ErrInvalidInput)
+	}
+	subject := strings.TrimRight(in.Subject, " \t")
+	body := strings.TrimRight(in.Body, " \t\n")
+	if err := s.validateContent(subject, body); err != nil {
+		return Message{}, Recipient{}, err
+	}
+
+	sender, err := s.deps.Memberships.GetActiveMembership(ctx, in.GameID, in.SenderUserID)
+	if err != nil {
+		if errors.Is(err, ErrNotFound) {
+			return Message{}, Recipient{}, fmt.Errorf("%w: sender is not an active member of the game", ErrForbidden)
+		}
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: load sender membership: %w", err)
+	}
+	recipient, err := s.deps.Memberships.GetActiveMembership(ctx, in.GameID, in.RecipientUserID)
+	if err != nil {
+		if errors.Is(err, ErrNotFound) {
+			return Message{}, Recipient{}, fmt.Errorf("%w: recipient is not an active member of the game", ErrForbidden)
+		}
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: load recipient membership: %w", err)
+	}
+
+	username := sender.UserName
+	msgInsert := MessageInsert{
+		MessageID:      uuid.New(),
+		GameID:         in.GameID,
+		GameName:       sender.GameName,
+		Kind:           KindPersonal,
+		SenderKind:     SenderKindPlayer,
+		SenderUserID:   &in.SenderUserID,
+		SenderUsername: &username,
+		SenderIP:       in.SenderIP,
+		Subject:        subject,
+		Body:           body,
+		BodyLang:       s.deps.Detector.Detect(body),
+		BroadcastScope: BroadcastScopeSingle,
+	}
+	raceName := recipient.RaceName
+	rcptInsert := buildRecipientInsert(
+		msgInsert.MessageID,
+		MemberSnapshot{
+			UserID:            in.RecipientUserID,
+			GameID:            in.GameID,
+			GameName:          recipient.GameName,
+			UserName:          recipient.UserName,
+			RaceName:          raceName,
+			PreferredLanguage: recipient.PreferredLanguage,
+			Status:            "active",
+		},
+		msgInsert.BodyLang,
+		s.nowUTC(),
+	)
+
+	msg, recipients, err := s.deps.Store.InsertMessageWithRecipients(ctx, msgInsert, []RecipientInsert{rcptInsert})
+	if err != nil {
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: send personal: %w", err)
+	}
+	if len(recipients) != 1 {
+		return Message{}, Recipient{}, fmt.Errorf("diplomail: send personal: unexpected recipient count %d", len(recipients))
+	}
+
+	if recipients[0].AvailableAt != nil {
+		s.publishMessageReceived(ctx, msg, recipients[0])
+	}
+	return msg, recipients[0], nil
+}
+
+// GetMessage returns the InboxEntry for messageID addressed to
+// userID. ErrNotFound is returned when the caller is not a recipient
+// of the message — handlers translate that to 404 so the existence
+// of the message is not leaked. The same sentinel is returned when
+// the caller is no longer an active member of the game and the
+// message is personal-kind: post-kick visibility is restricted to
+// admin/system mail (item 8 of the spec).
+//
+// When `targetLang` is non-empty and differs from the message's
+// `body_lang`, the function consults the translation cache; on a
+// miss it asks the configured Translator to produce a rendering and
+// persists the result. The noop translator returns the input
+// unchanged with `engine == "noop"`, which is treated as
+// "translation unavailable" — the entry comes back with `Translation
+// == nil` and the caller renders the original body.
+func (s *Service) GetMessage(ctx context.Context, userID, messageID uuid.UUID, targetLang string) (InboxEntry, error) {
+	entry, err := s.deps.Store.LoadInboxEntry(ctx, messageID, userID)
+	if err != nil {
+		return InboxEntry{}, err
+	}
+	allowed, err := s.allowedKinds(ctx, entry.GameID, userID)
+	if err != nil {
+		return InboxEntry{}, err
+	}
+	if !allowed[entry.Kind] {
+		return InboxEntry{}, ErrNotFound
+	}
+	if tr := s.resolveTranslation(ctx, entry.Message, targetLang); tr != nil {
+		entry.Translation = tr
+	}
+	return entry, nil
+}
+
+// resolveTranslation returns the cached translation for
+// (message, targetLang), lazily computing and persisting one on
+// cache miss. Returns nil when no translation is needed (target is
+// empty, matches `body_lang`, or the message body is itself
+// undetermined) or when the configured translator declares the
+// rendering unavailable.
+func (s *Service) resolveTranslation(ctx context.Context, msg Message, targetLang string) *Translation {
+	if targetLang == "" || targetLang == msg.BodyLang || msg.BodyLang == LangUndetermined {
+		return nil
+	}
+	if existing, err := s.deps.Store.LoadTranslation(ctx, msg.MessageID, targetLang); err == nil {
+		t := existing
+		return &t
+	} else if !errors.Is(err, ErrNotFound) {
+		s.deps.Logger.Warn("load translation failed",
+			zap.String("message_id", msg.MessageID.String()),
+			zap.String("target_lang", targetLang),
+			zap.Error(err))
+		return nil
+	}
+	if s.deps.Translator == nil {
+		return nil
+	}
+	result, err := s.deps.Translator.Translate(ctx, msg.BodyLang, targetLang, msg.Subject, msg.Body)
+	if err != nil {
+		s.deps.Logger.Warn("translator call failed",
+			zap.String("message_id", msg.MessageID.String()),
+			zap.String("target_lang", targetLang),
+			zap.Error(err))
+		return nil
+	}
+	if result.Engine == "" || result.Engine == "noop" {
+		return nil
+	}
+	tr := Translation{
+		TranslationID:    uuid.New(),
+		MessageID:        msg.MessageID,
+		TargetLang:       targetLang,
+		TranslatedSubject: result.Subject,
+		TranslatedBody:   result.Body,
+		Translator:       result.Engine,
+	}
+	stored, err := s.deps.Store.InsertTranslation(ctx, tr)
+	if err != nil {
+		s.deps.Logger.Warn("insert translation failed",
+			zap.String("message_id", msg.MessageID.String()),
+			zap.String("target_lang", targetLang),
+			zap.Error(err))
+		return nil
+	}
+	return &stored
+}
+
+// ListInbox returns every non-deleted message addressed to userID in
+// gameID, newest first. Read state is preserved per entry; the HTTP
+// layer renders both the message and the recipient row. Personal
+// messages are filtered out when the caller is no longer an active
+// member of the game so a kicked player keeps read access to the
+// admin/system explanation of the kick but not to historical
+// player-to-player threads.
+//
+// When `targetLang` is non-empty and differs from a row's body
+// language, the function consults the translation cache (without
+// re-translating on miss; the per-message read endpoint owns that
+// path so the bulk listing never blocks on translator I/O).
+func (s *Service) ListInbox(ctx context.Context, gameID, userID uuid.UUID, targetLang string) ([]InboxEntry, error) {
+	entries, err := s.deps.Store.ListInbox(ctx, gameID, userID)
+	if err != nil {
+		return nil, err
+	}
+	allowed, err := s.allowedKinds(ctx, gameID, userID)
+	if err != nil {
+		return nil, err
+	}
+	out := entries
+	if !(allowed[KindPersonal] && allowed[KindAdmin]) {
+		out = make([]InboxEntry, 0, len(entries))
+		for _, e := range entries {
+			if allowed[e.Kind] {
+				out = append(out, e)
+			}
+		}
+	}
+	if targetLang == "" {
+		return out, nil
+	}
+	for i := range out {
+		out[i].Translation = s.lookupCachedTranslation(ctx, out[i].Message, targetLang)
+	}
+	return out, nil
+}
+
+// lookupCachedTranslation reads an existing translation row without
+// asking the Translator to compute one. The bulk inbox listing uses
+// this to avoid per-row translator I/O; GetMessage uses the full
+// `resolveTranslation` helper which falls through to the translator
+// on cache miss.
+func (s *Service) lookupCachedTranslation(ctx context.Context, msg Message, targetLang string) *Translation {
+	if targetLang == "" || targetLang == msg.BodyLang || msg.BodyLang == LangUndetermined {
+		return nil
+	}
+	existing, err := s.deps.Store.LoadTranslation(ctx, msg.MessageID, targetLang)
+	if err != nil {
+		if !errors.Is(err, ErrNotFound) {
+			s.deps.Logger.Debug("inbox translation lookup failed",
+				zap.String("message_id", msg.MessageID.String()),
+				zap.Error(err))
+		}
+		return nil
+	}
+	out := existing
+	return &out
+}
+
+// allowedKinds resolves the set of message kinds the caller may read
+// in gameID. An active member can read everything; a former member
+// (status removed or blocked) can read admin-kind only. A user who
+// has never been a member of the game but is still listed as a
+// recipient (legacy / system message) is granted the same admin-only
+// view. The function never returns an empty set: even non-members
+// keep their read access to admin mail.
+func (s *Service) allowedKinds(ctx context.Context, gameID, userID uuid.UUID) (map[string]bool, error) {
+	if s.deps.Memberships == nil {
+		return map[string]bool{KindPersonal: true, KindAdmin: true}, nil
+	}
+	if _, err := s.deps.Memberships.GetActiveMembership(ctx, gameID, userID); err == nil {
+		return map[string]bool{KindPersonal: true, KindAdmin: true}, nil
+	} else if !errors.Is(err, ErrNotFound) {
+		return nil, err
+	}
+	return map[string]bool{KindAdmin: true}, nil
+}
+
+// ListSent returns personal messages authored by senderUserID in
+// gameID, newest first. Admin/system rows have no `sender_user_id`
+// and are therefore excluded; the user surface does not need them.
+func (s *Service) ListSent(ctx context.Context, gameID, senderUserID uuid.UUID) ([]Message, error) {
+	return s.deps.Store.ListSent(ctx, gameID, senderUserID)
+}
+
+// MarkRead transitions a recipient row to `read`. Idempotent: a
+// second call on an already-read row is a no-op. Returns the
+// resulting Recipient. ErrNotFound is surfaced when the caller is
+// not a recipient of the message.
+func (s *Service) MarkRead(ctx context.Context, userID, messageID uuid.UUID) (Recipient, error) {
+	return s.deps.Store.MarkRead(ctx, messageID, userID, s.nowUTC())
+}
+
+// DeleteMessage soft-deletes the recipient row identified by
+// (messageID, userID). The row must already have `read_at` set, or
+// the call returns ErrConflict (item 10 of the spec: open-then-delete).
+// Returns ErrNotFound when the caller is not a recipient.
+func (s *Service) DeleteMessage(ctx context.Context, userID, messageID uuid.UUID) (Recipient, error) {
+	return s.deps.Store.SoftDelete(ctx, messageID, userID, s.nowUTC())
+}
+
+// UnreadCountsForUser returns the lobby badge breakdown.
+func (s *Service) UnreadCountsForUser(ctx context.Context, userID uuid.UUID) ([]UnreadCount, error) {
+	return s.deps.Store.UnreadCountsForUser(ctx, userID)
+}
+
+// validateContent enforces the body/subject byte limits and rejects
+// non-UTF-8 input. Stage A applies the rules to plain text only; HTML
+// is treated as plain text by the server (the UI renders via
+// textContent) and gets no special handling.
+func (s *Service) validateContent(subject, body string) error {
+	if body == "" {
+		return fmt.Errorf("%w: body must not be empty", ErrInvalidInput)
+	}
+	if !utf8.ValidString(body) {
+		return fmt.Errorf("%w: body must be valid UTF-8", ErrInvalidInput)
+	}
+	if len(body) > s.deps.Config.MaxBodyBytes {
+		return fmt.Errorf("%w: body exceeds %d bytes", ErrInvalidInput, s.deps.Config.MaxBodyBytes)
+	}
+	if subject != "" {
+		if !utf8.ValidString(subject) {
+			return fmt.Errorf("%w: subject must be valid UTF-8", ErrInvalidInput)
+		}
+		if len(subject) > s.deps.Config.MaxSubjectBytes {
+			return fmt.Errorf("%w: subject exceeds %d bytes", ErrInvalidInput, s.deps.Config.MaxSubjectBytes)
+		}
+	}
+	return nil
+}
+
+// publishMessageReceived emits the per-recipient push notification.
+// Failures are logged at debug level: notifications are best-effort
+// over the gRPC stream, and clients always have the unread-counts
+// endpoint as the durable fallback.
+func (s *Service) publishMessageReceived(ctx context.Context, msg Message, recipient Recipient) {
+	unreadGame, err := s.deps.Store.UnreadCountForUserGame(ctx, msg.GameID, recipient.UserID)
+	if err != nil {
+		s.deps.Logger.Warn("compute unread count for push payload failed",
+			zap.String("message_id", msg.MessageID.String()),
+			zap.String("recipient", recipient.UserID.String()),
+			zap.Error(err))
+		unreadGame = 0
+	}
+	unreadTotals, err := s.deps.Store.UnreadCountsForUser(ctx, recipient.UserID)
+	if err != nil {
+		s.deps.Logger.Warn("compute unread totals for push payload failed",
+			zap.String("recipient", recipient.UserID.String()),
+			zap.Error(err))
+		unreadTotals = nil
+	}
+	unreadTotal := 0
+	for _, u := range unreadTotals {
+		unreadTotal += u.Unread
+	}
+
+	payload := map[string]any{
+		"message_id":   msg.MessageID.String(),
+		"game_id":      msg.GameID.String(),
+		"kind":         msg.Kind,
+		"sender_kind":  msg.SenderKind,
+		"subject":      msg.Subject,
+		"preview":      preview(msg.Body, previewMaxRunes),
+		"preview_lang": msg.BodyLang,
+		"unread_total": unreadTotal,
+		"unread_game":  unreadGame,
+	}
+	ev := DiplomailNotification{
+		Kind:           "diplomail.message.received",
+		IdempotencyKey: "diplomail.message.received:" + msg.MessageID.String() + ":" + recipient.UserID.String(),
+		Recipient:      recipient.UserID,
+		Payload:        payload,
+	}
+	if err := s.deps.Notification.PublishDiplomailEvent(ctx, ev); err != nil {
+		s.deps.Logger.Warn("publish diplomail event failed",
+			zap.String("message_id", msg.MessageID.String()),
+			zap.String("recipient", recipient.UserID.String()),
+			zap.Error(err))
+	}
+}
+
+// preview truncates s to at most max runes and appends a horizontal
+// ellipsis when truncation actually happened. The function operates
+// on runes, not bytes, so multibyte UTF-8 sequences (Cyrillic,
+// emoji) survive without corruption.
+func preview(s string, max int) string {
+	if max <= 0 || utf8.RuneCountInString(s) <= max {
+		return s
+	}
+	count := 0
+	for i := range s {
+		if count == max {
+			return s[:i] + "…"
+		}
+		count++
+	}
+	return s
+}

backend/internal/diplomail/store.go

@@ -0,0 +1,803 @@
+package diplomail
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+
+	"galaxy/backend/internal/postgres/jet/backend/model"
+	"galaxy/backend/internal/postgres/jet/backend/table"
+
+	"github.com/go-jet/jet/v2/postgres"
+	"github.com/go-jet/jet/v2/qrm"
+	"github.com/google/uuid"
+)
+
+// Store is the Postgres-backed query surface for the diplomail
+// package. All queries are built through go-jet against the generated
+// table bindings under `backend/internal/postgres/jet/backend/table`.
+type Store struct {
+	db *sql.DB
+}
+
+// NewStore constructs a Store wrapping db.
+func NewStore(db *sql.DB) *Store { return &Store{db: db} }
+
+// messageColumns is the canonical projection for diplomail_messages
+// reads.
+func messageColumns() postgres.ColumnList {
+	m := table.DiplomailMessages
+	return postgres.ColumnList{
+		m.MessageID, m.GameID, m.GameName, m.Kind, m.SenderKind,
+		m.SenderUserID, m.SenderUsername, m.SenderIP,
+		m.Subject, m.Body, m.BodyLang, m.BroadcastScope, m.CreatedAt,
+	}
+}
+
+// recipientColumns is the canonical projection for
+// diplomail_recipients reads.
+func recipientColumns() postgres.ColumnList {
+	r := table.DiplomailRecipients
+	return postgres.ColumnList{
+		r.RecipientID, r.MessageID, r.GameID, r.UserID,
+		r.RecipientUserName, r.RecipientRaceName, r.RecipientPreferredLanguage,
+		r.AvailableAt, r.TranslationAttempts, r.NextTranslationAttemptAt,
+		r.DeliveredAt, r.ReadAt, r.DeletedAt, r.NotifiedAt,
+	}
+}
+
+// MessageInsert carries the immutable per-message fields. The store
+// fills MessageID, sets CreatedAt to `now()` via the column default,
+// and leaves recipient-side state to InsertRecipient.
+type MessageInsert struct {
+	MessageID      uuid.UUID
+	GameID         uuid.UUID
+	GameName       string
+	Kind           string
+	SenderKind     string
+	SenderUserID   *uuid.UUID
+	SenderUsername *string
+	SenderIP       string
+	Subject        string
+	Body           string
+	BodyLang       string
+	BroadcastScope string
+}
+
+// RecipientInsert carries the per-recipient snapshot. AvailableAt
+// captures the async-delivery contract: when non-nil, the recipient
+// row is materialised already-delivered (no translation needed or
+// the language matches); when nil, the recipient is queued for the
+// translation worker.
+type RecipientInsert struct {
+	RecipientID                uuid.UUID
+	MessageID                  uuid.UUID
+	GameID                     uuid.UUID
+	UserID                     uuid.UUID
+	RecipientUserName          string
+	RecipientRaceName          *string
+	RecipientPreferredLanguage string
+	AvailableAt                *time.Time
+}
+
+// InsertMessageWithRecipients persists a Message together with one or
+// more Recipient rows inside a single transaction. The function is
+// the canonical write path for every send variant: Stage A passes a
+// single-element slice; later stages reuse the same path for
+// broadcasts.
+func (s *Store) InsertMessageWithRecipients(ctx context.Context, msg MessageInsert, recipients []RecipientInsert) (Message, []Recipient, error) {
+	if len(recipients) == 0 {
+		return Message{}, nil, errors.New("diplomail store: at least one recipient required")
+	}
+
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail store: begin tx: %w", err)
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	m := table.DiplomailMessages
+	msgStmt := m.INSERT(
+		m.MessageID, m.GameID, m.GameName, m.Kind, m.SenderKind,
+		m.SenderUserID, m.SenderUsername, m.SenderIP,
+		m.Subject, m.Body, m.BodyLang, m.BroadcastScope,
+	).VALUES(
+		msg.MessageID,
+		msg.GameID,
+		msg.GameName,
+		msg.Kind,
+		msg.SenderKind,
+		uuidPtrArg(msg.SenderUserID),
+		stringPtrArg(msg.SenderUsername),
+		msg.SenderIP,
+		msg.Subject,
+		msg.Body,
+		msg.BodyLang,
+		msg.BroadcastScope,
+	).RETURNING(messageColumns())
+
+	var msgRow model.DiplomailMessages
+	if err := msgStmt.QueryContext(ctx, tx, &msgRow); err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail store: insert message: %w", err)
+	}
+
+	r := table.DiplomailRecipients
+	rcptStmt := r.INSERT(
+		r.RecipientID, r.MessageID, r.GameID, r.UserID,
+		r.RecipientUserName, r.RecipientRaceName,
+		r.RecipientPreferredLanguage, r.AvailableAt,
+	)
+	for _, in := range recipients {
+		rcptStmt = rcptStmt.VALUES(
+			in.RecipientID,
+			in.MessageID,
+			in.GameID,
+			in.UserID,
+			in.RecipientUserName,
+			stringPtrArg(in.RecipientRaceName),
+			in.RecipientPreferredLanguage,
+			timePtrArg(in.AvailableAt),
+		)
+	}
+	rcptStmt = rcptStmt.RETURNING(recipientColumns())
+
+	var rcptRows []model.DiplomailRecipients
+	if err := rcptStmt.QueryContext(ctx, tx, &rcptRows); err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail store: insert recipients: %w", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		return Message{}, nil, fmt.Errorf("diplomail store: commit: %w", err)
+	}
+
+	return messageFromModel(msgRow), recipientsFromModel(rcptRows), nil
+}
+
+// LoadMessage returns the Message row identified by messageID. The
+// function is used by readers that already verified recipient
+// authorisation; callers that need both the message and the
+// recipient's per-user state should use LoadInboxEntry.
+func (s *Store) LoadMessage(ctx context.Context, messageID uuid.UUID) (Message, error) {
+	m := table.DiplomailMessages
+	stmt := postgres.SELECT(messageColumns()).
+		FROM(m).
+		WHERE(m.MessageID.EQ(postgres.UUID(messageID))).
+		LIMIT(1)
+	var row model.DiplomailMessages
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return Message{}, ErrNotFound
+		}
+		return Message{}, fmt.Errorf("diplomail store: load message %s: %w", messageID, err)
+	}
+	return messageFromModel(row), nil
+}
+
+// LoadInboxEntry returns a Message together with the caller's
+// Recipient row, both for messageID. Returns ErrNotFound when the
+// caller is not a recipient of the message — this is also how the
+// service layer enforces "only recipients may read".
+func (s *Store) LoadInboxEntry(ctx context.Context, messageID, userID uuid.UUID) (InboxEntry, error) {
+	m := table.DiplomailMessages
+	r := table.DiplomailRecipients
+	cols := append(messageColumns(), recipientColumns()...)
+	stmt := postgres.SELECT(cols).
+		FROM(r.INNER_JOIN(m, m.MessageID.EQ(r.MessageID))).
+		WHERE(
+			r.MessageID.EQ(postgres.UUID(messageID)).
+				AND(r.UserID.EQ(postgres.UUID(userID))),
+		).
+		LIMIT(1)
+	var dest struct {
+		model.DiplomailMessages
+		Recipient model.DiplomailRecipients `alias:"diplomail_recipients"`
+	}
+	if err := stmt.QueryContext(ctx, s.db, &dest); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return InboxEntry{}, ErrNotFound
+		}
+		return InboxEntry{}, fmt.Errorf("diplomail store: load inbox entry %s/%s: %w", messageID, userID, err)
+	}
+	return InboxEntry{
+		Message:   messageFromModel(dest.DiplomailMessages),
+		Recipient: recipientFromModel(dest.Recipient),
+	}, nil
+}
+
+// ListInbox returns the recipient view of messages addressed to
+// userID in gameID, newest first. Soft-deleted rows
+// (`deleted_at IS NOT NULL`) are excluded. Rows still waiting for
+// the async translation worker (`available_at IS NULL`) are also
+// excluded — they will appear once delivery is complete.
+func (s *Store) ListInbox(ctx context.Context, gameID, userID uuid.UUID) ([]InboxEntry, error) {
+	m := table.DiplomailMessages
+	r := table.DiplomailRecipients
+	cols := append(messageColumns(), recipientColumns()...)
+	stmt := postgres.SELECT(cols).
+		FROM(r.INNER_JOIN(m, m.MessageID.EQ(r.MessageID))).
+		WHERE(
+			r.UserID.EQ(postgres.UUID(userID)).
+				AND(r.GameID.EQ(postgres.UUID(gameID))).
+				AND(r.DeletedAt.IS_NULL()).
+				AND(r.AvailableAt.IS_NOT_NULL()),
+		).
+		ORDER_BY(m.CreatedAt.DESC(), m.MessageID.DESC())
+	var dest []struct {
+		model.DiplomailMessages
+		Recipient model.DiplomailRecipients `alias:"diplomail_recipients"`
+	}
+	if err := stmt.QueryContext(ctx, s.db, &dest); err != nil {
+		return nil, fmt.Errorf("diplomail store: list inbox %s/%s: %w", gameID, userID, err)
+	}
+	out := make([]InboxEntry, 0, len(dest))
+	for _, row := range dest {
+		out = append(out, InboxEntry{
+			Message:   messageFromModel(row.DiplomailMessages),
+			Recipient: recipientFromModel(row.Recipient),
+		})
+	}
+	return out, nil
+}
+
+// ListSent returns messages authored by senderUserID in gameID,
+// newest first. Personal messages only — admin/system rows have
+// `sender_user_id IS NULL` and are filtered out by the WHERE clause.
+func (s *Store) ListSent(ctx context.Context, gameID, senderUserID uuid.UUID) ([]Message, error) {
+	m := table.DiplomailMessages
+	stmt := postgres.SELECT(messageColumns()).
+		FROM(m).
+		WHERE(
+			m.GameID.EQ(postgres.UUID(gameID)).
+				AND(m.SenderUserID.EQ(postgres.UUID(senderUserID))),
+		).
+		ORDER_BY(m.CreatedAt.DESC(), m.MessageID.DESC())
+	var rows []model.DiplomailMessages
+	if err := stmt.QueryContext(ctx, s.db, &rows); err != nil {
+		return nil, fmt.Errorf("diplomail store: list sent %s/%s: %w", gameID, senderUserID, err)
+	}
+	out := make([]Message, 0, len(rows))
+	for _, row := range rows {
+		out = append(out, messageFromModel(row))
+	}
+	return out, nil
+}
+
+// MarkRead sets `read_at = at` on the recipient row identified by
+// (messageID, userID). Idempotent: a row that is already marked read
+// is left untouched but the existing Recipient is returned.
+// Returns ErrNotFound when the user is not a recipient of the message.
+func (s *Store) MarkRead(ctx context.Context, messageID, userID uuid.UUID, at time.Time) (Recipient, error) {
+	r := table.DiplomailRecipients
+	stmt := r.UPDATE(r.ReadAt).
+		SET(postgres.TimestampzT(at.UTC())).
+		WHERE(
+			r.MessageID.EQ(postgres.UUID(messageID)).
+				AND(r.UserID.EQ(postgres.UUID(userID))).
+				AND(r.ReadAt.IS_NULL()),
+		).
+		RETURNING(recipientColumns())
+	var row model.DiplomailRecipients
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if !errors.Is(err, qrm.ErrNoRows) {
+			return Recipient{}, fmt.Errorf("diplomail store: mark read %s/%s: %w", messageID, userID, err)
+		}
+		// The row exists but read_at was already set, or the row
+		// does not exist at all. Fetch to disambiguate.
+		existing, loadErr := s.LoadRecipient(ctx, messageID, userID)
+		if loadErr != nil {
+			return Recipient{}, loadErr
+		}
+		return existing, nil
+	}
+	return recipientFromModel(row), nil
+}
+
+// SoftDelete sets `deleted_at = at` on the recipient row identified by
+// (messageID, userID). The row must already have `read_at` set;
+// otherwise the call returns ErrConflict so a hostile client cannot
+// erase a message before opening it (item 10 of the spec).
+// Returns ErrNotFound when the user is not a recipient.
+func (s *Store) SoftDelete(ctx context.Context, messageID, userID uuid.UUID, at time.Time) (Recipient, error) {
+	r := table.DiplomailRecipients
+	stmt := r.UPDATE(r.DeletedAt).
+		SET(postgres.TimestampzT(at.UTC())).
+		WHERE(
+			r.MessageID.EQ(postgres.UUID(messageID)).
+				AND(r.UserID.EQ(postgres.UUID(userID))).
+				AND(r.ReadAt.IS_NOT_NULL()).
+				AND(r.DeletedAt.IS_NULL()),
+		).
+		RETURNING(recipientColumns())
+	var row model.DiplomailRecipients
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if !errors.Is(err, qrm.ErrNoRows) {
+			return Recipient{}, fmt.Errorf("diplomail store: soft delete %s/%s: %w", messageID, userID, err)
+		}
+		existing, loadErr := s.LoadRecipient(ctx, messageID, userID)
+		if loadErr != nil {
+			return Recipient{}, loadErr
+		}
+		if existing.ReadAt == nil {
+			return Recipient{}, fmt.Errorf("%w: message must be read before delete", ErrConflict)
+		}
+		// Already deleted: return the existing row idempotently.
+		return existing, nil
+	}
+	return recipientFromModel(row), nil
+}
+
+// LoadRecipient fetches the Recipient row keyed on (messageID, userID).
+// Returns ErrNotFound when no such recipient exists.
+func (s *Store) LoadRecipient(ctx context.Context, messageID, userID uuid.UUID) (Recipient, error) {
+	r := table.DiplomailRecipients
+	stmt := postgres.SELECT(recipientColumns()).
+		FROM(r).
+		WHERE(
+			r.MessageID.EQ(postgres.UUID(messageID)).
+				AND(r.UserID.EQ(postgres.UUID(userID))),
+		).
+		LIMIT(1)
+	var row model.DiplomailRecipients
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return Recipient{}, ErrNotFound
+		}
+		return Recipient{}, fmt.Errorf("diplomail store: load recipient %s/%s: %w", messageID, userID, err)
+	}
+	return recipientFromModel(row), nil
+}
+
+// UnreadCountForUserGame returns the count of unread, non-deleted,
+// delivered messages addressed to userID in gameID. Recipients
+// still waiting for translation (`available_at IS NULL`) are
+// excluded so the badge does not flicker.
+func (s *Store) UnreadCountForUserGame(ctx context.Context, gameID, userID uuid.UUID) (int, error) {
+	r := table.DiplomailRecipients
+	stmt := postgres.SELECT(postgres.COUNT(postgres.STAR).AS("count")).
+		FROM(r).
+		WHERE(
+			r.UserID.EQ(postgres.UUID(userID)).
+				AND(r.GameID.EQ(postgres.UUID(gameID))).
+				AND(r.ReadAt.IS_NULL()).
+				AND(r.DeletedAt.IS_NULL()).
+				AND(r.AvailableAt.IS_NOT_NULL()),
+		)
+	var dest struct {
+		Count int64 `alias:"count"`
+	}
+	if err := stmt.QueryContext(ctx, s.db, &dest); err != nil {
+		return 0, fmt.Errorf("diplomail store: unread count %s/%s: %w", gameID, userID, err)
+	}
+	return int(dest.Count), nil
+}
+
+// PendingTranslationPair carries one unit of work picked by the
+// translation worker. Multiple recipients of the same message that
+// share a preferred_language collapse into one pair, because the
+// translation is shared via the diplomail_translations cache.
+// CurrentAttempts is the highest `translation_attempts` value across
+// the matching recipient rows, so the worker can decide whether the
+// next attempt is the last one before falling back.
+type PendingTranslationPair struct {
+	MessageID       uuid.UUID
+	TargetLang      string
+	CurrentAttempts int32
+}
+
+// PickPendingTranslationPair returns one pair eligible for the
+// translation worker, or `ok == false` when the queue is empty. The
+// pair is the (message, target_lang) of any recipient where
+// `available_at IS NULL` and `next_translation_attempt_at` is either
+// unset or already due. The query intentionally drops the
+// `FOR UPDATE` clause — the worker is single-threaded per process,
+// and the optimistic UPDATE in `MarkPairDelivered` /
+// `MarkPairFallback` filters by `available_at IS NULL`, so a stale
+// pickup never delivers twice.
+func (s *Store) PickPendingTranslationPair(ctx context.Context, now time.Time) (PendingTranslationPair, bool, error) {
+	r := table.DiplomailRecipients
+	stmt := postgres.SELECT(
+		r.MessageID.AS("message_id"),
+		r.RecipientPreferredLanguage.AS("target_lang"),
+		postgres.MAX(r.TranslationAttempts).AS("attempts"),
+	).
+		FROM(r).
+		WHERE(
+			r.AvailableAt.IS_NULL().
+				AND(r.RecipientPreferredLanguage.NOT_EQ(postgres.String(""))).
+				AND(r.NextTranslationAttemptAt.IS_NULL().
+					OR(r.NextTranslationAttemptAt.LT_EQ(postgres.TimestampzT(now.UTC())))),
+		).
+		GROUP_BY(r.MessageID, r.RecipientPreferredLanguage).
+		ORDER_BY(r.MessageID.ASC(), r.RecipientPreferredLanguage.ASC()).
+		LIMIT(1)
+	var dest struct {
+		MessageID  uuid.UUID `alias:"message_id"`
+		TargetLang string    `alias:"target_lang"`
+		Attempts   int32     `alias:"attempts"`
+	}
+	if err := stmt.QueryContext(ctx, s.db, &dest); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return PendingTranslationPair{}, false, nil
+		}
+		return PendingTranslationPair{}, false, fmt.Errorf("diplomail store: pick pending pair: %w", err)
+	}
+	if dest.MessageID == (uuid.UUID{}) {
+		return PendingTranslationPair{}, false, nil
+	}
+	return PendingTranslationPair{
+		MessageID:       dest.MessageID,
+		TargetLang:      dest.TargetLang,
+		CurrentAttempts: dest.Attempts,
+	}, true, nil
+}
+
+// MarkPairDelivered flips every still-pending recipient of (messageID,
+// targetLang) to `available_at = at`, optionally persisting the
+// translation row alongside in the same transaction. Returns the
+// recipients that were just delivered (used by the worker to fan out
+// push events).
+func (s *Store) MarkPairDelivered(ctx context.Context, messageID uuid.UUID, targetLang string, translation *Translation, at time.Time) ([]Recipient, error) {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return nil, fmt.Errorf("diplomail store: begin deliver tx: %w", err)
+	}
+	defer func() { _ = tx.Rollback() }()
+
+	if translation != nil {
+		t := table.DiplomailTranslations
+		ins := t.INSERT(
+			t.TranslationID, t.MessageID, t.TargetLang,
+			t.TranslatedSubject, t.TranslatedBody, t.Translator,
+		).VALUES(
+			translation.TranslationID, translation.MessageID, translation.TargetLang,
+			translation.TranslatedSubject, translation.TranslatedBody, translation.Translator,
+		).ON_CONFLICT(t.MessageID, t.TargetLang).DO_NOTHING()
+		if _, err := ins.ExecContext(ctx, tx); err != nil {
+			return nil, fmt.Errorf("diplomail store: upsert translation: %w", err)
+		}
+	}
+
+	r := table.DiplomailRecipients
+	upd := r.UPDATE(r.AvailableAt, r.NextTranslationAttemptAt).
+		SET(postgres.TimestampzT(at.UTC()), postgres.NULL).
+		WHERE(
+			r.MessageID.EQ(postgres.UUID(messageID)).
+				AND(r.RecipientPreferredLanguage.EQ(postgres.String(targetLang))).
+				AND(r.AvailableAt.IS_NULL()),
+		).
+		RETURNING(recipientColumns())
+
+	var rows []model.DiplomailRecipients
+	if err := upd.QueryContext(ctx, tx, &rows); err != nil {
+		return nil, fmt.Errorf("diplomail store: mark pair delivered: %w", err)
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, fmt.Errorf("diplomail store: commit deliver: %w", err)
+	}
+	out := make([]Recipient, 0, len(rows))
+	for _, row := range rows {
+		out = append(out, recipientFromModel(row))
+	}
+	return out, nil
+}
+
+// SchedulePairRetry bumps the attempt counter and schedules the next
+// translation attempt for `next`. The recipient rows stay in the
+// pending queue (`available_at IS NULL`). Returns the new attempt
+// counter so the worker can decide whether to fall back to the
+// original on the next pickup.
+func (s *Store) SchedulePairRetry(ctx context.Context, messageID uuid.UUID, targetLang string, next time.Time) (int32, error) {
+	r := table.DiplomailRecipients
+	upd := r.UPDATE(r.TranslationAttempts, r.NextTranslationAttemptAt).
+		SET(r.TranslationAttempts.ADD(postgres.Int(1)), postgres.TimestampzT(next.UTC())).
+		WHERE(
+			r.MessageID.EQ(postgres.UUID(messageID)).
+				AND(r.RecipientPreferredLanguage.EQ(postgres.String(targetLang))).
+				AND(r.AvailableAt.IS_NULL()),
+		).
+		RETURNING(r.TranslationAttempts)
+	var dest []struct {
+		TranslationAttempts int32 `alias:"diplomail_recipients.translation_attempts"`
+	}
+	if err := upd.QueryContext(ctx, s.db, &dest); err != nil {
+		return 0, fmt.Errorf("diplomail store: schedule pair retry: %w", err)
+	}
+	if len(dest) == 0 {
+		return 0, nil
+	}
+	max := dest[0].TranslationAttempts
+	for _, d := range dest[1:] {
+		if d.TranslationAttempts > max {
+			max = d.TranslationAttempts
+		}
+	}
+	return max, nil
+}
+
+// translationColumns is the canonical projection for
+// diplomail_translations reads.
+func translationColumns() postgres.ColumnList {
+	t := table.DiplomailTranslations
+	return postgres.ColumnList{
+		t.TranslationID, t.MessageID, t.TargetLang,
+		t.TranslatedSubject, t.TranslatedBody, t.Translator, t.TranslatedAt,
+	}
+}
+
+// LoadTranslation returns the cached translation row for
+// (messageID, targetLang). Returns ErrNotFound when no cache row
+// exists yet — the caller decides whether to compute and persist
+// one.
+func (s *Store) LoadTranslation(ctx context.Context, messageID uuid.UUID, targetLang string) (Translation, error) {
+	t := table.DiplomailTranslations
+	stmt := postgres.SELECT(translationColumns()).
+		FROM(t).
+		WHERE(t.MessageID.EQ(postgres.UUID(messageID)).
+			AND(t.TargetLang.EQ(postgres.String(targetLang)))).
+		LIMIT(1)
+	var row model.DiplomailTranslations
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return Translation{}, ErrNotFound
+		}
+		return Translation{}, fmt.Errorf("diplomail store: load translation %s/%s: %w", messageID, targetLang, err)
+	}
+	return translationFromModel(row), nil
+}
+
+// InsertTranslation persists a new translation cache row. The unique
+// constraint on (message_id, target_lang) prevents duplicate
+// renderings. Callers that race on the same (message, lang) pair
+// should be prepared for a UNIQUE violation; the second writer can
+// fall back to LoadTranslation.
+func (s *Store) InsertTranslation(ctx context.Context, in Translation) (Translation, error) {
+	t := table.DiplomailTranslations
+	stmt := t.INSERT(
+		t.TranslationID, t.MessageID, t.TargetLang,
+		t.TranslatedSubject, t.TranslatedBody, t.Translator,
+	).VALUES(
+		in.TranslationID, in.MessageID, in.TargetLang,
+		in.TranslatedSubject, in.TranslatedBody, in.Translator,
+	).RETURNING(translationColumns())
+
+	var row model.DiplomailTranslations
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		return Translation{}, fmt.Errorf("diplomail store: insert translation %s/%s: %w", in.MessageID, in.TargetLang, err)
+	}
+	return translationFromModel(row), nil
+}
+
+func translationFromModel(row model.DiplomailTranslations) Translation {
+	return Translation{
+		TranslationID:    row.TranslationID,
+		MessageID:        row.MessageID,
+		TargetLang:       row.TargetLang,
+		TranslatedSubject: row.TranslatedSubject,
+		TranslatedBody:   row.TranslatedBody,
+		Translator:       row.Translator,
+		TranslatedAt:     row.TranslatedAt,
+	}
+}
+
+// DeleteMessagesForGames removes every diplomail_messages row whose
+// game_id falls in the supplied set. The cascade defined on the
+// `diplomail_recipients` and `diplomail_translations` foreign keys
+// removes the per-recipient state and the cached translations in
+// the same transaction. Returns the count of messages removed.
+//
+// Used by the admin bulk-purge endpoint; callers are expected to
+// have already filtered the input set to terminal-state games.
+func (s *Store) DeleteMessagesForGames(ctx context.Context, gameIDs []uuid.UUID) (int, error) {
+	if len(gameIDs) == 0 {
+		return 0, nil
+	}
+	args := make([]postgres.Expression, 0, len(gameIDs))
+	for _, id := range gameIDs {
+		args = append(args, postgres.UUID(id))
+	}
+	m := table.DiplomailMessages
+	stmt := m.DELETE().WHERE(m.GameID.IN(args...))
+	res, err := stmt.ExecContext(ctx, s.db)
+	if err != nil {
+		return 0, fmt.Errorf("diplomail store: bulk delete messages: %w", err)
+	}
+	affected, err := res.RowsAffected()
+	if err != nil {
+		return 0, fmt.Errorf("diplomail store: rows affected: %w", err)
+	}
+	return int(affected), nil
+}
+
+// ListMessagesForAdmin returns a paginated slice of messages
+// matching filter. The result is ordered by created_at DESC,
+// message_id DESC. Total is the count without pagination so the
+// caller can render a "page X of N" envelope.
+func (s *Store) ListMessagesForAdmin(ctx context.Context, filter AdminMessageListing) ([]Message, int, error) {
+	m := table.DiplomailMessages
+	page := filter.Page
+	if page < 1 {
+		page = 1
+	}
+	pageSize := filter.PageSize
+	if pageSize < 1 {
+		pageSize = 50
+	}
+
+	conditions := postgres.BoolExpression(nil)
+	addCondition := func(cond postgres.BoolExpression) {
+		if conditions == nil {
+			conditions = cond
+			return
+		}
+		conditions = conditions.AND(cond)
+	}
+	if filter.GameID != nil {
+		addCondition(m.GameID.EQ(postgres.UUID(*filter.GameID)))
+	}
+	if filter.Kind != "" {
+		addCondition(m.Kind.EQ(postgres.String(filter.Kind)))
+	}
+	if filter.SenderKind != "" {
+		addCondition(m.SenderKind.EQ(postgres.String(filter.SenderKind)))
+	}
+
+	countStmt := postgres.SELECT(postgres.COUNT(postgres.STAR).AS("count")).FROM(m)
+	if conditions != nil {
+		countStmt = countStmt.WHERE(conditions)
+	}
+	var countDest struct {
+		Count int64 `alias:"count"`
+	}
+	if err := countStmt.QueryContext(ctx, s.db, &countDest); err != nil {
+		return nil, 0, fmt.Errorf("diplomail store: count admin messages: %w", err)
+	}
+
+	listStmt := postgres.SELECT(messageColumns()).FROM(m)
+	if conditions != nil {
+		listStmt = listStmt.WHERE(conditions)
+	}
+	listStmt = listStmt.
+		ORDER_BY(m.CreatedAt.DESC(), m.MessageID.DESC()).
+		LIMIT(int64(pageSize)).
+		OFFSET(int64((page - 1) * pageSize))
+
+	var rows []model.DiplomailMessages
+	if err := listStmt.QueryContext(ctx, s.db, &rows); err != nil {
+		return nil, 0, fmt.Errorf("diplomail store: list admin messages: %w", err)
+	}
+	out := make([]Message, 0, len(rows))
+	for _, row := range rows {
+		out = append(out, messageFromModel(row))
+	}
+	return out, int(countDest.Count), nil
+}
+
+// UnreadCountsForUser returns a per-game breakdown of unread messages
+// addressed to userID, plus the matching game names so the lobby
+// badge UI can render entries even after the recipient's membership
+// has been revoked. The slice is ordered by game name.
+func (s *Store) UnreadCountsForUser(ctx context.Context, userID uuid.UUID) ([]UnreadCount, error) {
+	r := table.DiplomailRecipients
+	m := table.DiplomailMessages
+	stmt := postgres.SELECT(
+		r.GameID.AS("game_id"),
+		postgres.MAX(m.GameName).AS("game_name"),
+		postgres.COUNT(postgres.STAR).AS("count"),
+	).
+		FROM(r.INNER_JOIN(m, m.MessageID.EQ(r.MessageID))).
+		WHERE(
+			r.UserID.EQ(postgres.UUID(userID)).
+				AND(r.ReadAt.IS_NULL()).
+				AND(r.DeletedAt.IS_NULL()).
+				AND(r.AvailableAt.IS_NOT_NULL()),
+		).
+		GROUP_BY(r.GameID).
+		ORDER_BY(postgres.MAX(m.GameName).ASC())
+	var dest []struct {
+		GameID   uuid.UUID `alias:"game_id"`
+		GameName string    `alias:"game_name"`
+		Count    int64     `alias:"count"`
+	}
+	if err := stmt.QueryContext(ctx, s.db, &dest); err != nil {
+		return nil, fmt.Errorf("diplomail store: unread counts %s: %w", userID, err)
+	}
+	out := make([]UnreadCount, 0, len(dest))
+	for _, row := range dest {
+		out = append(out, UnreadCount{
+			GameID:   row.GameID,
+			GameName: row.GameName,
+			Unread:   int(row.Count),
+		})
+	}
+	return out, nil
+}
+
+// messageFromModel converts a jet-generated row to the domain type.
+func messageFromModel(row model.DiplomailMessages) Message {
+	out := Message{
+		MessageID:      row.MessageID,
+		GameID:         row.GameID,
+		GameName:       row.GameName,
+		Kind:           row.Kind,
+		SenderKind:     row.SenderKind,
+		SenderIP:       row.SenderIP,
+		Subject:        row.Subject,
+		Body:           row.Body,
+		BodyLang:       row.BodyLang,
+		BroadcastScope: row.BroadcastScope,
+		CreatedAt:      row.CreatedAt,
+	}
+	if row.SenderUserID != nil {
+		id := *row.SenderUserID
+		out.SenderUserID = &id
+	}
+	if row.SenderUsername != nil {
+		name := *row.SenderUsername
+		out.SenderUsername = &name
+	}
+	return out
+}
+
+// recipientFromModel converts a jet-generated row to the domain type.
+func recipientFromModel(row model.DiplomailRecipients) Recipient {
+	out := Recipient{
+		RecipientID:                row.RecipientID,
+		MessageID:                  row.MessageID,
+		GameID:                     row.GameID,
+		UserID:                     row.UserID,
+		RecipientUserName:          row.RecipientUserName,
+		RecipientPreferredLanguage: row.RecipientPreferredLanguage,
+		AvailableAt:                row.AvailableAt,
+		TranslationAttempts:        row.TranslationAttempts,
+		NextTranslationAttemptAt:   row.NextTranslationAttemptAt,
+		DeliveredAt:                row.DeliveredAt,
+		ReadAt:                     row.ReadAt,
+		DeletedAt:                  row.DeletedAt,
+		NotifiedAt:                 row.NotifiedAt,
+	}
+	if row.RecipientRaceName != nil {
+		name := *row.RecipientRaceName
+		out.RecipientRaceName = &name
+	}
+	return out
+}
+
+// recipientsFromModel converts a slice in place. Used by
+// InsertMessageWithRecipients.
+func recipientsFromModel(rows []model.DiplomailRecipients) []Recipient {
+	out := make([]Recipient, 0, len(rows))
+	for _, row := range rows {
+		out = append(out, recipientFromModel(row))
+	}
+	return out
+}
+
+// uuidPtrArg returns the jet argument expression for a nullable UUID.
+// Pre-NULL handling here avoids a custom NULL literal at every call
+// site.
+func uuidPtrArg(v *uuid.UUID) postgres.Expression {
+	if v == nil {
+		return postgres.NULL
+	}
+	return postgres.UUID(*v)
+}
+
+// stringPtrArg returns the jet argument expression for a nullable
+// text column.
+func stringPtrArg(v *string) postgres.Expression {
+	if v == nil {
+		return postgres.NULL
+	}
+	return postgres.String(*v)
+}
+
+// timePtrArg returns the jet argument expression for a nullable
+// timestamptz column.
+func timePtrArg(v *time.Time) postgres.Expression {
+	if v == nil {
+		return postgres.NULL
+	}
+	return postgres.TimestampzT(v.UTC())
+}

backend/internal/diplomail/translator/libretranslate.go

@@ -0,0 +1,154 @@
+package translator
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// LibreTranslateEngine is the engine identifier persisted in
+// `diplomail_translations.translator` for cache rows produced by the
+// LibreTranslate client.
+const LibreTranslateEngine = "libretranslate"
+
+// LibreTranslateConfig configures the HTTP client. URL is the base
+// of the deployed instance (without `/translate`). Timeout bounds a
+// single HTTP request; the worker layers retry / backoff on top.
+type LibreTranslateConfig struct {
+	URL     string
+	Timeout time.Duration
+}
+
+// ErrUnsupportedLanguagePair classifies a LibreTranslate 400 response
+// that indicates the engine cannot translate between the requested
+// source / target codes. The worker treats this as terminal: no
+// further retries, deliver the original.
+var ErrUnsupportedLanguagePair = errors.New("translator: language pair not supported by libretranslate")
+
+// NewLibreTranslate constructs a Translator that posts to
+// `<URL>/translate`. Returns an error when URL is empty so wiring
+// catches "translator misconfigured" at startup rather than at
+// first-translation-attempt.
+func NewLibreTranslate(cfg LibreTranslateConfig) (Translator, error) {
+	url := strings.TrimRight(strings.TrimSpace(cfg.URL), "/")
+	if url == "" {
+		return nil, errors.New("translator: libretranslate URL must be set")
+	}
+	timeout := cfg.Timeout
+	if timeout <= 0 {
+		timeout = 10 * time.Second
+	}
+	return &libreTranslate{
+		endpoint: url + "/translate",
+		client:   &http.Client{Timeout: timeout},
+	}, nil
+}
+
+type libreTranslate struct {
+	endpoint string
+	client   *http.Client
+}
+
+// requestBody is the LibreTranslate POST /translate input shape.
+// `q` is sent as a two-element array so the engine returns one
+// translation per element in the same call (subject + body).
+type requestBody struct {
+	Q      []string `json:"q"`
+	Source string   `json:"source"`
+	Target string   `json:"target"`
+	Format string   `json:"format"`
+}
+
+// responseBody is the LibreTranslate output shape when `q` is an
+// array. The single-string-q variant is a different shape; we never
+// emit a single-q request so the client always sees the array form.
+type responseBody struct {
+	TranslatedText []string `json:"translatedText"`
+	Error          string   `json:"error,omitempty"`
+}
+
+// Translate posts subject + body to LibreTranslate, normalising the
+// language codes and classifying the response. The 400 / unsupported-
+// pair path is signalled by `ErrUnsupportedLanguagePair`. All other
+// HTTP errors (timeout, 5xx, network failure) come back as wrapped
+// errors so the worker can backoff and retry.
+func (l *libreTranslate) Translate(ctx context.Context, srcLang, dstLang, subject, body string) (Result, error) {
+	src := normaliseLanguageCode(srcLang)
+	dst := normaliseLanguageCode(dstLang)
+	if src == "" || dst == "" {
+		return Result{}, fmt.Errorf("translator: missing source or target language (src=%q dst=%q)", srcLang, dstLang)
+	}
+	if src == dst {
+		return Result{Subject: subject, Body: body, Engine: NoopEngine}, nil
+	}
+
+	reqBody, err := json.Marshal(requestBody{
+		Q:      []string{subject, body},
+		Source: src,
+		Target: dst,
+		Format: "text",
+	})
+	if err != nil {
+		return Result{}, fmt.Errorf("translator: marshal request: %w", err)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, l.endpoint, bytes.NewReader(reqBody))
+	if err != nil {
+		return Result{}, fmt.Errorf("translator: build request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := l.client.Do(req)
+	if err != nil {
+		return Result{}, fmt.Errorf("translator: do request: %w", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	raw, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	if err != nil {
+		return Result{}, fmt.Errorf("translator: read response: %w", err)
+	}
+	if resp.StatusCode == http.StatusBadRequest {
+		return Result{}, fmt.Errorf("%w: %s", ErrUnsupportedLanguagePair, strings.TrimSpace(string(raw)))
+	}
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return Result{}, fmt.Errorf("translator: libretranslate http %d: %s", resp.StatusCode, strings.TrimSpace(string(raw)))
+	}
+
+	var out responseBody
+	if err := json.Unmarshal(raw, &out); err != nil {
+		return Result{}, fmt.Errorf("translator: unmarshal response: %w", err)
+	}
+	if out.Error != "" {
+		return Result{}, fmt.Errorf("translator: libretranslate error: %s", out.Error)
+	}
+	if len(out.TranslatedText) != 2 {
+		return Result{}, fmt.Errorf("translator: libretranslate returned %d strings, want 2", len(out.TranslatedText))
+	}
+	return Result{
+		Subject: out.TranslatedText[0],
+		Body:    out.TranslatedText[1],
+		Engine:  LibreTranslateEngine,
+	}, nil
+}
+
+// normaliseLanguageCode collapses a BCP 47 tag to the ISO 639-1 base
+// that LibreTranslate expects (`en-US` → `en`, `EN` → `en`). The
+// helper is mirrored on the diplomail service side; both sides need
+// to use the same normalisation so cache keys line up.
+func normaliseLanguageCode(tag string) string {
+	tag = strings.TrimSpace(tag)
+	if tag == "" {
+		return ""
+	}
+	if i := strings.IndexAny(tag, "-_"); i > 0 {
+		tag = tag[:i]
+	}
+	return strings.ToLower(tag)
+}

backend/internal/diplomail/translator/libretranslate_test.go

@@ -0,0 +1,173 @@
+package translator
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestLibreTranslateHappyPath(t *testing.T) {
+	t.Parallel()
+	var (
+		requestSource string
+		requestTarget string
+		requestQ      []string
+		requestFormat string
+	)
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body, _ := io.ReadAll(r.Body)
+		var in requestBody
+		if err := json.Unmarshal(body, &in); err != nil {
+			t.Errorf("unmarshal: %v", err)
+		}
+		requestSource = in.Source
+		requestTarget = in.Target
+		requestQ = in.Q
+		requestFormat = in.Format
+		_ = json.NewEncoder(w).Encode(responseBody{
+			TranslatedText: []string{"[ru] " + in.Q[0], "[ru] " + in.Q[1]},
+		})
+	}))
+	t.Cleanup(server.Close)
+
+	tr, err := NewLibreTranslate(LibreTranslateConfig{URL: server.URL, Timeout: 2 * time.Second})
+	if err != nil {
+		t.Fatalf("new: %v", err)
+	}
+	res, err := tr.Translate(context.Background(), "en", "ru", "Hello", "World")
+	if err != nil {
+		t.Fatalf("translate: %v", err)
+	}
+	if res.Engine != LibreTranslateEngine {
+		t.Fatalf("engine = %q, want %q", res.Engine, LibreTranslateEngine)
+	}
+	if res.Subject != "[ru] Hello" || res.Body != "[ru] World" {
+		t.Fatalf("result = %+v", res)
+	}
+	if requestSource != "en" || requestTarget != "ru" || requestFormat != "text" {
+		t.Fatalf("request fields: src=%q dst=%q fmt=%q", requestSource, requestTarget, requestFormat)
+	}
+	if len(requestQ) != 2 || requestQ[0] != "Hello" || requestQ[1] != "World" {
+		t.Fatalf("request q = %v", requestQ)
+	}
+}
+
+func TestLibreTranslateNormalisesLanguageCodes(t *testing.T) {
+	t.Parallel()
+	var src, dst string
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body, _ := io.ReadAll(r.Body)
+		var in requestBody
+		_ = json.Unmarshal(body, &in)
+		src, dst = in.Source, in.Target
+		_ = json.NewEncoder(w).Encode(responseBody{TranslatedText: []string{"a", "b"}})
+	}))
+	t.Cleanup(server.Close)
+
+	tr, _ := NewLibreTranslate(LibreTranslateConfig{URL: server.URL})
+	if _, err := tr.Translate(context.Background(), "EN-US", "ru-RU", "x", "y"); err != nil {
+		t.Fatalf("translate: %v", err)
+	}
+	if src != "en" || dst != "ru" {
+		t.Fatalf("normalised codes src=%q dst=%q, want en/ru", src, dst)
+	}
+}
+
+func TestLibreTranslateUnsupportedPair(t *testing.T) {
+	t.Parallel()
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusBadRequest)
+		_, _ = w.Write([]byte(`{"error":"language not supported"}`))
+	}))
+	t.Cleanup(server.Close)
+
+	tr, _ := NewLibreTranslate(LibreTranslateConfig{URL: server.URL})
+	_, err := tr.Translate(context.Background(), "en", "xx", "subject", "body")
+	if !errors.Is(err, ErrUnsupportedLanguagePair) {
+		t.Fatalf("err = %v, want ErrUnsupportedLanguagePair", err)
+	}
+}
+
+func TestLibreTranslateServerError(t *testing.T) {
+	t.Parallel()
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusInternalServerError)
+		_, _ = w.Write([]byte("kaboom"))
+	}))
+	t.Cleanup(server.Close)
+
+	tr, _ := NewLibreTranslate(LibreTranslateConfig{URL: server.URL})
+	_, err := tr.Translate(context.Background(), "en", "ru", "subject", "body")
+	if err == nil {
+		t.Fatalf("expected error, got nil")
+	}
+	if errors.Is(err, ErrUnsupportedLanguagePair) {
+		t.Fatalf("err mis-classified as unsupported pair: %v", err)
+	}
+	if !strings.Contains(err.Error(), "500") {
+		t.Fatalf("err = %v, want mention of 500", err)
+	}
+}
+
+func TestLibreTranslateSameSourceAndTargetIsNoop(t *testing.T) {
+	t.Parallel()
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Errorf("translator should not call the server for identical src/dst: %s", r.URL.Path)
+	}))
+	t.Cleanup(server.Close)
+
+	tr, _ := NewLibreTranslate(LibreTranslateConfig{URL: server.URL})
+	res, err := tr.Translate(context.Background(), "en", "EN", "x", "y")
+	if err != nil {
+		t.Fatalf("translate: %v", err)
+	}
+	if res.Engine != NoopEngine {
+		t.Fatalf("engine = %q, want %q", res.Engine, NoopEngine)
+	}
+}
+
+func TestLibreTranslateRequiresURL(t *testing.T) {
+	t.Parallel()
+	_, err := NewLibreTranslate(LibreTranslateConfig{URL: ""})
+	if err == nil {
+		t.Fatalf("expected error for empty URL")
+	}
+}
+
+// TestLibreTranslateRejectsMalformedArray defends against a server
+// that returns a partial / unexpected `translatedText` payload. The
+// client must surface an error (not panic, not return a half-empty
+// Result) so the worker can decide between retry and fallback.
+func TestLibreTranslateRejectsMalformedArray(t *testing.T) {
+	t.Parallel()
+	cases := []struct {
+		name string
+		body string
+	}{
+		{"single string", `{"translatedText": "only one"}`},
+		{"array of one", `{"translatedText": ["only one"]}`},
+		{"empty array", `{"translatedText": []}`},
+		{"missing field", `{"foo":"bar"}`},
+	}
+	for _, tc := range cases {
+		body := tc.body
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+				_, _ = w.Write([]byte(body))
+			}))
+			t.Cleanup(server.Close)
+			tr, _ := NewLibreTranslate(LibreTranslateConfig{URL: server.URL})
+			res, err := tr.Translate(context.Background(), "en", "ru", "subject", "body")
+			if err == nil {
+				t.Fatalf("expected error for malformed body %q, got %+v", body, res)
+			}
+		})
+	}
+}

backend/internal/diplomail/translator/translator.go

@@ -0,0 +1,59 @@
+// Package translator wraps the per-language rendering for the
+// diplomail subsystem. The package exposes a narrow `Translator`
+// interface so the actual translation backend (LibreTranslate, an
+// in-process model, a SaaS engine, …) can be swapped without
+// touching the rest of the codebase.
+//
+// Stage D ships a `NoopTranslator` that returns the input unchanged.
+// The diplomail Service treats a `Name == NoopEngine` result as
+// "translation unavailable" and refrains from writing a cache row;
+// the inbox handler then returns the original body with a
+// `translated == false` payload. The contract lets the rest of the
+// system ship without a translation backend; future stages can wire
+// a real `Translator` without code changes elsewhere.
+package translator
+
+import "context"
+
+// NoopEngine is the engine identifier returned by `NoopTranslator`.
+// The diplomail Service checks for this value to decide whether to
+// persist a `diplomail_translations` row.
+const NoopEngine = "noop"
+
+// Result carries one translated rendering plus the engine identifier
+// that produced it. The engine name is persisted as
+// `diplomail_translations.translator` so an operator can see which
+// backend produced each row.
+type Result struct {
+	Subject string
+	Body    string
+	Engine  string
+}
+
+// Translator is the read-only surface diplomail consumes when it
+// needs to render a message for a recipient whose
+// `preferred_language` differs from `body_lang`. Implementations
+// must be safe for concurrent use; `Translate` may be invoked from
+// the async worker on many messages at once.
+type Translator interface {
+	// Translate renders `subject` and `body` from `srcLang` into
+	// `dstLang`. A nil error with `Result.Engine == NoopEngine`
+	// signals that no real rendering happened.
+	Translate(ctx context.Context, srcLang, dstLang, subject, body string) (Result, error)
+}
+
+// NewNoop returns a Translator that always returns the input
+// unchanged with engine name `NoopEngine`.
+func NewNoop() Translator {
+	return noop{}
+}
+
+type noop struct{}
+
+func (noop) Translate(_ context.Context, _, _, subject, body string) (Result, error) {
+	return Result{
+		Subject: subject,
+		Body:    body,
+		Engine:  NoopEngine,
+	}, nil
+}

backend/internal/diplomail/types.go

@@ -0,0 +1,255 @@
+package diplomail
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+)
+
+// Message mirrors a row in `backend.diplomail_messages` enriched with
+// the per-message metadata captured at insert time.
+//
+// SenderUserID and SenderUsername are nullable in the DB so that the
+// CHECK constraint can cover the three legal sender shapes:
+//
+//   - player: SenderUserID set, SenderUsername set
+//   - admin:  SenderUserID nil, SenderUsername set
+//   - system: SenderUserID nil, SenderUsername nil
+type Message struct {
+	MessageID      uuid.UUID
+	GameID         uuid.UUID
+	GameName       string
+	Kind           string
+	SenderKind     string
+	SenderUserID   *uuid.UUID
+	SenderUsername *string
+	SenderIP       string
+	Subject        string
+	Body           string
+	BodyLang       string
+	BroadcastScope string
+	CreatedAt      time.Time
+}
+
+// Recipient mirrors a row in `backend.diplomail_recipients`. The
+// per-recipient state (read/deleted/delivered/notified) lives here.
+// RecipientUserName, RecipientRaceName, and
+// RecipientPreferredLanguage are snapshots taken at insert time so
+// the inbox listing, admin search, and translation worker render
+// correctly even after the source rows are renamed or revoked.
+//
+// AvailableAt encodes the async-translation contract introduced in
+// Stage E:
+//
+//   - non-nil → message is visible to the recipient (in inbox /
+//     unread counts / push events) starting from this timestamp;
+//   - nil → recipient is waiting for the translation worker to fan
+//     out the translated rendering. The translation_attempts counter
+//     tracks the number of failed LibreTranslate calls; the worker
+//     gives up after `MaxTranslationAttempts` and falls back to the
+//     original body, flipping AvailableAt to now().
+type Recipient struct {
+	RecipientID                uuid.UUID
+	MessageID                  uuid.UUID
+	GameID                     uuid.UUID
+	UserID                     uuid.UUID
+	RecipientUserName          string
+	RecipientRaceName          *string
+	RecipientPreferredLanguage string
+	AvailableAt                *time.Time
+	TranslationAttempts        int32
+	NextTranslationAttemptAt   *time.Time
+	DeliveredAt                *time.Time
+	ReadAt                     *time.Time
+	DeletedAt                  *time.Time
+	NotifiedAt                 *time.Time
+}
+
+// InboxEntry is the read-side projection composed of a Message and the
+// caller's own Recipient row. The HTTP layer renders one of these per
+// item in the inbox listing. Translation, when non-nil, carries the
+// per-recipient rendering returned from
+// `Service.GetMessage(ctx, …, targetLang)` and surfaced under the
+// `body_translated` payload field; Stage D ships a noop translator,
+// so this field stays nil until a real backend is wired.
+type InboxEntry struct {
+	Message
+	Recipient   Recipient
+	Translation *Translation
+}
+
+// Translation mirrors a row in `backend.diplomail_translations`. The
+// engine identifier is preserved so an operator can see which
+// backend produced the cached rendering.
+type Translation struct {
+	TranslationID    uuid.UUID
+	MessageID        uuid.UUID
+	TargetLang       string
+	TranslatedSubject string
+	TranslatedBody   string
+	Translator       string
+	TranslatedAt     time.Time
+}
+
+// SendPersonalInput is the request payload for SendPersonal: the
+// caller sending a single-recipient personal message. Validation
+// (active membership, body length, etc.) is performed inside the
+// service.
+type SendPersonalInput struct {
+	GameID          uuid.UUID
+	SenderUserID    uuid.UUID
+	RecipientUserID uuid.UUID
+	Subject         string
+	Body            string
+	SenderIP        string
+}
+
+// CallerKind enumerates the privileged sender roles for admin-kind
+// messages. Owners (`CallerKindOwner`) are players who own a private
+// game; admins (`CallerKindAdmin`) hit the dedicated admin route;
+// `CallerKindSystem` is reserved for internal lifecycle hooks.
+const (
+	CallerKindOwner  = "owner"
+	CallerKindAdmin  = "admin"
+	CallerKindSystem = "system"
+)
+
+// SendAdminPersonalInput is the request payload for an owner /
+// admin / system sending an admin-kind message to a single
+// recipient. Authorization (owner-vs-admin distinction) is enforced
+// by the HTTP layer; the service trusts the caller designation.
+type SendAdminPersonalInput struct {
+	GameID          uuid.UUID
+	CallerKind      string
+	CallerUserID    *uuid.UUID
+	CallerUsername  string
+	RecipientUserID uuid.UUID
+	Subject         string
+	Body            string
+	SenderIP        string
+}
+
+// SendAdminBroadcastInput is the request payload for an owner /
+// admin / system broadcasting an admin-kind message inside a single
+// game. RecipientScope selects the address book; the sender's own
+// recipient row is never created (a broadcast author does not get a
+// copy of their own message).
+type SendAdminBroadcastInput struct {
+	GameID         uuid.UUID
+	CallerKind     string
+	CallerUserID   *uuid.UUID
+	CallerUsername string
+	RecipientScope string
+	Subject        string
+	Body           string
+	SenderIP       string
+}
+
+// LifecycleEventKind enumerates the producer-side intents the lobby
+// emits when a game-state or membership-state transition lands.
+const (
+	LifecycleKindGamePaused          = "game.paused"
+	LifecycleKindGameCancelled       = "game.cancelled"
+	LifecycleKindMembershipRemoved   = "membership.removed"
+	LifecycleKindMembershipBlocked   = "membership.blocked"
+)
+
+// SendPlayerBroadcastInput is the request payload for the paid-tier
+// player broadcast. The sender is a player; recipients are the
+// active members of the game minus the sender. The resulting message
+// is `kind="personal"`, `sender_kind="player"`,
+// `broadcast_scope="game_broadcast"` — recipients may reply as if it
+// were a personal send, but the reply goes back to the broadcaster
+// only.
+type SendPlayerBroadcastInput struct {
+	GameID       uuid.UUID
+	SenderUserID uuid.UUID
+	Subject      string
+	Body         string
+	SenderIP     string
+}
+
+// MultiGameBroadcastScope enumerates the admin multi-game broadcast
+// modes. `selected` requires `GameIDs`; `all_running` enumerates
+// every game whose status is non-terminal through GameLookup.
+const (
+	MultiGameScopeSelected   = "selected"
+	MultiGameScopeAllRunning = "all_running"
+)
+
+// SendMultiGameBroadcastInput is the request payload for the admin
+// multi-game broadcast. The service materialises one message row per
+// addressed game (so a recipient who plays in two games receives two
+// independently-deletable inbox entries), then fan-outs the push
+// events.
+type SendMultiGameBroadcastInput struct {
+	CallerUsername string
+	Scope          string
+	GameIDs        []uuid.UUID
+	RecipientScope string
+	Subject        string
+	Body           string
+	SenderIP       string
+}
+
+// BulkCleanupInput selects messages eligible for purge. OlderThanYears
+// must be >= 1; the service translates the value into a cutoff
+// expressed in years and walks `GameLookup.ListFinishedGamesBefore`.
+type BulkCleanupInput struct {
+	OlderThanYears int
+}
+
+// CleanupResult summarises a bulk-cleanup run for the admin response
+// envelope.
+type CleanupResult struct {
+	GameIDs        []uuid.UUID
+	MessagesDeleted int
+}
+
+// AdminMessageListing is the filter passed to ListMessagesForAdmin.
+// Pagination uses (Page, PageSize) consistent with the rest of the
+// admin surface. Filters are AND-combined; the empty filter returns
+// every persisted row.
+type AdminMessageListing struct {
+	Page     int
+	PageSize int
+	GameID   *uuid.UUID
+	Kind     string
+	SenderKind string
+}
+
+// AdminMessagePage is the canonical pagination envelope.
+type AdminMessagePage struct {
+	Items    []Message
+	Total    int
+	Page     int
+	PageSize int
+}
+
+// LifecycleEvent is the payload lobby hands to PublishLifecycle when
+// a transition needs to be reflected as durable system mail. The
+// recipient set is derived by the service:
+//
+//   - For game.* events the message fans out to every active member
+//     of the game except the actor (the actor sees the action in
+//     their own UI through other channels).
+//   - For membership.* events the message addresses exactly
+//     `TargetUser` (the kicked player), regardless of their current
+//     membership status — this is how a kicked player retains read
+//     access to the explanation of the kick.
+type LifecycleEvent struct {
+	GameID     uuid.UUID
+	Kind       string
+	Actor      string
+	Reason     string
+	TargetUser *uuid.UUID
+}
+
+// UnreadCount carries a per-game unread-count row returned by
+// UnreadCountsForUser. The lobby badge UI consumes the slice plus the
+// derived total.
+type UnreadCount struct {
+	GameID   uuid.UUID
+	GameName string
+	Unread   int
+}

backend/internal/diplomail/worker.go

@@ -0,0 +1,209 @@
+package diplomail
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"galaxy/backend/internal/diplomail/translator"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// translationBackoff returns the sleep applied before retry attempt
+// `attempt`. attempt is 1-indexed (the value the row carries AFTER
+// the failure is recorded). The schedule mirrors the spec —
+// 1s → 2s → 4s → 8s → 16s — so 5 failed attempts span ~31 seconds
+// before the worker falls back to delivering the original.
+func translationBackoff(attempt int32) time.Duration {
+	if attempt <= 0 {
+		return 0
+	}
+	out := time.Second
+	for i := int32(1); i < attempt; i++ {
+		out *= 2
+	}
+	const cap = 60 * time.Second
+	if out > cap {
+		return cap
+	}
+	return out
+}
+
+// Worker drives the async translation pipeline. Each tick picks a
+// single (message_id, target_lang) pair from
+// `diplomail_recipients` where `available_at IS NULL`, asks the
+// configured Translator to render the body, and either delivers the
+// pending recipients (success) or schedules a retry (transient
+// failure) or delivers them with a fallback to the original body
+// (terminal failure / max attempts).
+//
+// The worker is single-threaded by design: one HTTP call to
+// LibreTranslate at a time. This protects the upstream from spikes
+// and keeps the implementation reviewable.
+//
+// Implements `internal/app.Component` so it plugs into the same
+// lifecycle as the mail and notification workers.
+type Worker struct {
+	svc *Service
+}
+
+// NewWorker constructs a Worker bound to svc. Returning a non-nil
+// Worker even when the translator is the noop fallback is
+// intentional — the pickup query still works and falls through to
+// fallback delivery, which is the desired behaviour for setups
+// without LibreTranslate.
+func NewWorker(svc *Service) *Worker { return &Worker{svc: svc} }
+
+// Run drives the worker loop until ctx is cancelled.
+func (w *Worker) Run(ctx context.Context) error {
+	if w == nil || w.svc == nil {
+		return nil
+	}
+	logger := w.svc.deps.Logger.Named("worker")
+	interval := w.svc.deps.Config.WorkerInterval
+	if interval <= 0 {
+		interval = 2 * time.Second
+	}
+	if err := w.tick(ctx); err != nil && !errors.Is(err, context.Canceled) {
+		logger.Warn("diplomail worker initial tick failed", zap.Error(err))
+	}
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return nil
+		case <-ticker.C:
+			if err := w.tick(ctx); err != nil && !errors.Is(err, context.Canceled) {
+				logger.Warn("diplomail worker tick failed", zap.Error(err))
+			}
+		}
+	}
+}
+
+// Shutdown is a no-op: every translation outcome is committed inside
+// tick before returning, so cancelling the parent ctx is enough.
+func (w *Worker) Shutdown(_ context.Context) error { return nil }
+
+// Tick exposes the per-tick work for tests so they can drive the
+// worker without depending on the ticker.
+func (w *Worker) Tick(ctx context.Context) error { return w.tick(ctx) }
+
+// tick picks one pair from the queue and applies the result. The
+// per-tick budget is one pair on purpose: the worker is single
+// threaded and we do not want a fast LibreTranslate instance to
+// starve the rest of the backend's I/O behind a long-running batch.
+func (w *Worker) tick(ctx context.Context) error {
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+	pair, ok, err := w.svc.deps.Store.PickPendingTranslationPair(ctx, w.svc.nowUTC())
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return nil
+	}
+	return w.processPair(ctx, pair)
+}
+
+// processPair runs the full pipeline for one (message, target_lang).
+// Steps:
+//
+//  1. Load the source message.
+//  2. Check the translation cache. If a row already exists (another
+//     worker pre-populated it, or two pairs converged on the same
+//     target), reuse it and deliver.
+//  3. Otherwise call the configured Translator.
+//  4. Apply the outcome: success → cache + deliver; unsupported
+//     pair → deliver fallback (no cache row); other failure →
+//     schedule retry or deliver fallback after MaxAttempts.
+//  5. Fan out push events for every recipient whose `available_at`
+//     just transitioned.
+func (w *Worker) processPair(ctx context.Context, pair PendingTranslationPair) error {
+	logger := w.svc.deps.Logger.Named("worker").With(
+		zap.String("message_id", pair.MessageID.String()),
+		zap.String("target_lang", pair.TargetLang),
+	)
+	msg, err := w.svc.deps.Store.LoadMessage(ctx, pair.MessageID)
+	if err != nil {
+		return err
+	}
+
+	if cached, err := w.svc.deps.Store.LoadTranslation(ctx, pair.MessageID, pair.TargetLang); err == nil {
+		t := cached
+		return w.deliverPair(ctx, msg, pair.TargetLang, &t, logger)
+	} else if !errors.Is(err, ErrNotFound) {
+		return err
+	}
+
+	result, callErr := w.svc.deps.Translator.Translate(ctx, msg.BodyLang, pair.TargetLang, msg.Subject, msg.Body)
+	if callErr == nil && result.Engine != "" && result.Engine != translator.NoopEngine {
+		tr := Translation{
+			TranslationID:     uuid.New(),
+			MessageID:         msg.MessageID,
+			TargetLang:        pair.TargetLang,
+			TranslatedSubject: result.Subject,
+			TranslatedBody:    result.Body,
+			Translator:        result.Engine,
+		}
+		return w.deliverPair(ctx, msg, pair.TargetLang, &tr, logger)
+	}
+	if callErr == nil {
+		// Noop translator (or engine returned empty). Treat as
+		// "translation unavailable" — deliver fallback so users
+		// see the original.
+		logger.Debug("translator returned noop, delivering fallback")
+		return w.deliverPair(ctx, msg, pair.TargetLang, nil, logger)
+	}
+	if errors.Is(callErr, translator.ErrUnsupportedLanguagePair) {
+		logger.Info("language pair unsupported, delivering fallback", zap.Error(callErr))
+		return w.deliverPair(ctx, msg, pair.TargetLang, nil, logger)
+	}
+
+	// Transient failure — bump the attempts counter and schedule a
+	// retry. The next attempt timestamp is computed from the
+	// post-increment counter so the spec's 1s→2s→4s→8s→16s schedule
+	// applies between retries of the same pair.
+	maxAttempts := w.svc.deps.Config.TranslatorMaxAttempts
+	if maxAttempts <= 0 {
+		maxAttempts = 5
+	}
+	nextAttempt := pair.CurrentAttempts + 1
+	if int(nextAttempt) >= maxAttempts {
+		logger.Warn("translator max attempts reached, delivering fallback",
+			zap.Int32("attempts", nextAttempt), zap.Error(callErr))
+		return w.deliverPair(ctx, msg, pair.TargetLang, nil, logger)
+	}
+	next := w.svc.nowUTC().Add(translationBackoff(nextAttempt + 1))
+	if _, err := w.svc.deps.Store.SchedulePairRetry(ctx, pair.MessageID, pair.TargetLang, next); err != nil {
+		return err
+	}
+	logger.Info("translator attempt failed, scheduled retry",
+		zap.Int32("attempts", nextAttempt),
+		zap.Time("next_attempt_at", next),
+		zap.Error(callErr))
+	return nil
+}
+
+// deliverPair flips every still-pending recipient of (messageID,
+// targetLang) to delivered, optionally inserting the translation row
+// in the same transaction, and emits push events to the recipients
+// who were just unblocked.
+func (w *Worker) deliverPair(ctx context.Context, msg Message, targetLang string, translation *Translation, logger *zap.Logger) error {
+	recipients, err := w.svc.deps.Store.MarkPairDelivered(ctx, msg.MessageID, targetLang, translation, w.svc.nowUTC())
+	if err != nil {
+		return err
+	}
+	if len(recipients) == 0 {
+		logger.Debug("deliver yielded no recipients (already delivered)")
+		return nil
+	}
+	for _, r := range recipients {
+		w.svc.publishMessageReceived(ctx, msg, r)
+	}
+	return nil
+}
+

backend/internal/engineclient/client.go

@@ -26,6 +26,7 @@ const (
 	pathPlayerCommand   = "/api/v1/command"
 	pathPlayerOrder     = "/api/v1/order"
 	pathPlayerReport    = "/api/v1/report"
+	pathPlayerBattle    = "/api/v1/battle"
 	pathHealthz         = "/healthz"
 )
 
@@ -196,6 +197,46 @@ func (c *Client) PutOrders(ctx context.Context, baseURL string, payload json.Raw
 	return c.forwardPlayerWrite(ctx, baseURL, pathPlayerOrder, payload, "engine order")
 }
 
+// GetOrder calls `GET /api/v1/order?player=<raceName>&turn=<turn>` and
+// returns the engine response body verbatim. A `204 No Content` body
+// is signalled by `(nil, http.StatusNoContent, nil)` so callers can
+// surface "no stored order" without parsing the empty payload.
+// Other non-`200` statuses come back wrapped in `ErrEngineValidation`
+// (4xx) or `ErrEngineUnreachable` (everything else), matching the
+// existing player-write conventions.
+func (c *Client) GetOrder(ctx context.Context, baseURL, raceName string, turn int) (json.RawMessage, int, error) {
+	if err := validateBaseURL(baseURL); err != nil {
+		return nil, 0, err
+	}
+	if strings.TrimSpace(raceName) == "" {
+		return nil, 0, errors.New("engineclient order get: race name must not be empty")
+	}
+	if turn < 0 {
+		return nil, 0, fmt.Errorf("engineclient order get: turn must not be negative, got %d", turn)
+	}
+	values := url.Values{}
+	values.Set("player", raceName)
+	values.Set("turn", strconv.Itoa(turn))
+	target := baseURL + pathPlayerOrder + "?" + values.Encode()
+	body, status, doErr := c.doRequest(ctx, http.MethodGet, target, nil, c.probeTimeout)
+	if doErr != nil {
+		return nil, 0, fmt.Errorf("%w: engine order get: %w", ErrEngineUnreachable, doErr)
+	}
+	switch status {
+	case http.StatusOK:
+		if len(body) == 0 {
+			return nil, status, fmt.Errorf("%w: engine order get: empty response body", ErrEngineProtocolViolation)
+		}
+		return json.RawMessage(body), status, nil
+	case http.StatusNoContent:
+		return nil, status, nil
+	case http.StatusBadRequest, http.StatusConflict:
+		return json.RawMessage(body), status, fmt.Errorf("%w: engine order get: %s", ErrEngineValidation, summariseEngineError(body, status))
+	default:
+		return nil, status, fmt.Errorf("%w: engine order get: %s", ErrEngineUnreachable, summariseEngineError(body, status))
+	}
+}
+
 // GetReport calls `GET /api/v1/report?player=<raceName>&turn=<turn>`
 // and returns the engine response body verbatim.
 func (c *Client) GetReport(ctx context.Context, baseURL, raceName string, turn int) (json.RawMessage, error) {
@@ -229,6 +270,41 @@ func (c *Client) GetReport(ctx context.Context, baseURL, raceName string, turn i
 	}
 }
 
+// FetchBattle calls `GET /api/v1/battle/<turn>/<battleID>` and returns
+// the engine response body verbatim alongside the engine status code.
+// 200 carries the BattleReport JSON; 404 means the battle is unknown
+// and the body may be empty. Other 4xx statuses come back wrapped in
+// ErrEngineValidation, everything else in ErrEngineUnreachable.
+func (c *Client) FetchBattle(ctx context.Context, baseURL string, turn int, battleID string) (json.RawMessage, int, error) {
+	if err := validateBaseURL(baseURL); err != nil {
+		return nil, 0, err
+	}
+	if turn < 0 {
+		return nil, 0, fmt.Errorf("engineclient battle get: turn must not be negative, got %d", turn)
+	}
+	if strings.TrimSpace(battleID) == "" {
+		return nil, 0, errors.New("engineclient battle get: battle id must not be empty")
+	}
+	target := baseURL + pathPlayerBattle + "/" + strconv.Itoa(turn) + "/" + url.PathEscape(battleID)
+	body, status, doErr := c.doRequest(ctx, http.MethodGet, target, nil, c.probeTimeout)
+	if doErr != nil {
+		return nil, 0, fmt.Errorf("%w: engine battle get: %w", ErrEngineUnreachable, doErr)
+	}
+	switch status {
+	case http.StatusOK:
+		if len(body) == 0 {
+			return nil, status, fmt.Errorf("%w: engine battle get: empty response body", ErrEngineProtocolViolation)
+		}
+		return json.RawMessage(body), status, nil
+	case http.StatusNotFound:
+		return nil, status, nil
+	case http.StatusBadRequest, http.StatusConflict:
+		return json.RawMessage(body), status, fmt.Errorf("%w: engine battle get: %s", ErrEngineValidation, summariseEngineError(body, status))
+	default:
+		return nil, status, fmt.Errorf("%w: engine battle get: %s", ErrEngineUnreachable, summariseEngineError(body, status))
+	}
+}
+
 // Healthz calls `GET /healthz`. Returns nil on 2xx.
 func (c *Client) Healthz(ctx context.Context, baseURL string) error {
 	if err := validateBaseURL(baseURL); err != nil {

backend/internal/engineclient/client_test.go

@@ -195,6 +195,125 @@ func TestClientReportsForwardsQuery(t *testing.T) {
 	}
 }
 
+func TestClientGetOrderForwardsQuery(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != pathPlayerOrder {
+			t.Fatalf("unexpected path: %s", r.URL.Path)
+		}
+		if r.Method != http.MethodGet {
+			t.Fatalf("unexpected method: %s", r.Method)
+		}
+		if r.URL.Query().Get("player") != "alpha" {
+			t.Fatalf("player = %q", r.URL.Query().Get("player"))
+		}
+		if r.URL.Query().Get("turn") != "3" {
+			t.Fatalf("turn = %q", r.URL.Query().Get("turn"))
+		}
+		_, _ = w.Write([]byte(`{"game_id":"abc","updatedAt":99,"cmd":[]}`))
+	}))
+	t.Cleanup(srv.Close)
+
+	cli := newTestClient(t, srv)
+	body, status, err := cli.GetOrder(context.Background(), srv.URL, "alpha", 3)
+	if err != nil {
+		t.Fatalf("GetOrder: %v", err)
+	}
+	if status != http.StatusOK {
+		t.Fatalf("status = %d", status)
+	}
+	if !strings.Contains(string(body), `"updatedAt":99`) {
+		t.Fatalf("body = %s", body)
+	}
+}
+
+func TestClientGetOrderNoContent(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	t.Cleanup(srv.Close)
+
+	cli := newTestClient(t, srv)
+	body, status, err := cli.GetOrder(context.Background(), srv.URL, "alpha", 3)
+	if err != nil {
+		t.Fatalf("GetOrder: %v", err)
+	}
+	if status != http.StatusNoContent {
+		t.Fatalf("status = %d", status)
+	}
+	if body != nil {
+		t.Fatalf("expected nil body on 204, got %s", body)
+	}
+}
+
+func TestClientGetOrderRejectsBadInput(t *testing.T) {
+	cli := newTestClient(t, httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("server must not be hit on bad input")
+	})))
+	if _, _, err := cli.GetOrder(context.Background(), "http://example.com", "", 0); err == nil {
+		t.Fatal("expected error on empty race name")
+	}
+	if _, _, err := cli.GetOrder(context.Background(), "http://example.com", "alpha", -1); err == nil {
+		t.Fatal("expected error on negative turn")
+	}
+}
+
+func TestClientFetchBattleForwardsPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			t.Fatalf("unexpected method: %s", r.Method)
+		}
+		want := pathPlayerBattle + "/3/" + "11111111-1111-1111-1111-111111111111"
+		if r.URL.Path != want {
+			t.Fatalf("path = %q, want %q", r.URL.Path, want)
+		}
+		_, _ = w.Write([]byte(`{"id":"11111111-1111-1111-1111-111111111111","planet":4}`))
+	}))
+	t.Cleanup(srv.Close)
+
+	cli := newTestClient(t, srv)
+	body, status, err := cli.FetchBattle(context.Background(), srv.URL, 3, "11111111-1111-1111-1111-111111111111")
+	if err != nil {
+		t.Fatalf("FetchBattle: %v", err)
+	}
+	if status != http.StatusOK {
+		t.Fatalf("status = %d", status)
+	}
+	if !strings.Contains(string(body), `"planet":4`) {
+		t.Fatalf("body = %s", body)
+	}
+}
+
+func TestClientFetchBattleNotFound(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	t.Cleanup(srv.Close)
+
+	cli := newTestClient(t, srv)
+	body, status, err := cli.FetchBattle(context.Background(), srv.URL, 0, "11111111-1111-1111-1111-111111111111")
+	if err != nil {
+		t.Fatalf("FetchBattle: %v", err)
+	}
+	if status != http.StatusNotFound {
+		t.Fatalf("status = %d", status)
+	}
+	if body != nil {
+		t.Fatalf("expected nil body on 404, got %s", body)
+	}
+}
+
+func TestClientFetchBattleRejectsBadInput(t *testing.T) {
+	cli := newTestClient(t, httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("server must not be hit on bad input")
+	})))
+	if _, _, err := cli.FetchBattle(context.Background(), "http://example.com", -1, "11111111-1111-1111-1111-111111111111"); err == nil {
+		t.Fatal("expected error on negative turn")
+	}
+	if _, _, err := cli.FetchBattle(context.Background(), "http://example.com", 0, ""); err == nil {
+		t.Fatal("expected error on empty battle id")
+	}
+}
+
 func TestClientHealthzSuccess(t *testing.T) {
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.URL.Path != pathHealthz {

backend/internal/lobby/cache.go

@@ -117,6 +117,24 @@ func (c *Cache) GetGame(gameID uuid.UUID) (GameRecord, bool) {
 	return g, ok
 }
 
+// ListGames returns a snapshot copy of every cached game. Terminal-
+// state games (finished, cancelled) are evicted from the cache on
+// `PutGame`, so the result reflects the live roster of running /
+// paused / draft / starting / etc. games. The slice is freshly
+// allocated and safe for the caller to mutate.
+func (c *Cache) ListGames() []GameRecord {
+	if c == nil {
+		return nil
+	}
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	out := make([]GameRecord, 0, len(c.games))
+	for _, g := range c.games {
+		out = append(out, g)
+	}
+	return out
+}
+
 // PutGame stores game in the cache when its status is cacheable;
 // terminal statuses (finished, cancelled) cause the entry to be evicted.
 func (c *Cache) PutGame(game GameRecord) {

backend/internal/lobby/deps.go

@@ -51,6 +51,37 @@ type NotificationPublisher interface {
 	PublishLobbyEvent(ctx context.Context, intent LobbyNotification) error
 }
 
+// DiplomailPublisher is the outbound surface the lobby uses to drop a
+// durable system mail entry whenever a game-state or
+// membership-state transition needs to land in the affected players'
+// inboxes. The real implementation in `cmd/backend/main` adapts the
+// `*diplomail.Service.PublishLifecycle` call; tests and partial
+// wiring fall back to `NewNoopDiplomailPublisher`.
+type DiplomailPublisher interface {
+	PublishLifecycle(ctx context.Context, event LifecycleEvent) error
+}
+
+// LifecycleEvent is the open shape carried by a system-mail intent.
+// `Kind` is one of the lobby-internal constants
+// (`LifecycleKindGamePaused`, etc.). `TargetUser` is populated only
+// for membership-scoped events; the publisher derives the game-scoped
+// recipient set itself.
+type LifecycleEvent struct {
+	GameID     uuid.UUID
+	Kind       string
+	Actor      string
+	Reason     string
+	TargetUser *uuid.UUID
+}
+
+// Lifecycle-event kinds the lobby emits.
+const (
+	LifecycleKindGamePaused        = "game.paused"
+	LifecycleKindGameCancelled     = "game.cancelled"
+	LifecycleKindMembershipRemoved = "membership.removed"
+	LifecycleKindMembershipBlocked = "membership.blocked"
+)
+
 // LobbyNotification is the open shape carried by a notification intent.
 // The implementation emits a small set of `Kind` values matching the catalog in
 // `backend/README.md` §10. The `Payload` map is the kind-specific data
@@ -123,3 +154,26 @@ func (p *noopNotificationPublisher) PublishLobbyEvent(_ context.Context, intent
 	)
 	return nil
 }
+
+// NewNoopDiplomailPublisher returns a DiplomailPublisher that logs
+// every call at debug level and returns nil. Used by tests and by
+// the lobby Service factory when the Deps.Diplomail field is left
+// nil.
+func NewNoopDiplomailPublisher(logger *zap.Logger) DiplomailPublisher {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	return &noopDiplomailPublisher{logger: logger.Named("lobby.diplomail.noop")}
+}
+
+type noopDiplomailPublisher struct {
+	logger *zap.Logger
+}
+
+func (p *noopDiplomailPublisher) PublishLifecycle(_ context.Context, event LifecycleEvent) error {
+	p.logger.Debug("noop diplomail lifecycle",
+		zap.String("kind", event.Kind),
+		zap.String("game_id", event.GameID.String()),
+	)
+	return nil
+}

backend/internal/lobby/games.go

@@ -10,6 +10,7 @@ import (
 	"galaxy/cronutil"
 
 	"github.com/google/uuid"
+	"go.uber.org/zap"
 )
 
 // CreateGameInput is the parameter struct for Service.CreateGame.
@@ -233,6 +234,59 @@ func (s *Service) ListMyGames(ctx context.Context, userID uuid.UUID) ([]GameReco
 	return s.deps.Store.ListMyGames(ctx, userID)
 }
 
+// ListFinishedGamesBefore returns every game whose status is
+// `finished` or `cancelled` and whose `finished_at` is strictly older
+// than cutoff. The result walks the store through the admin-paged
+// query with a 200-row batch size; the caller is expected to invoke
+// this from rare admin workflows (diplomail bulk cleanup) rather
+// than hot-path reads.
+func (s *Service) ListFinishedGamesBefore(ctx context.Context, cutoff time.Time) ([]GameRecord, error) {
+	const pageSize = 200
+	page := 1
+	var out []GameRecord
+	for {
+		batch, _, err := s.deps.Store.ListAdminGames(ctx, page, pageSize)
+		if err != nil {
+			return nil, fmt.Errorf("lobby: list finished games before %s: %w", cutoff, err)
+		}
+		if len(batch) == 0 {
+			break
+		}
+		for _, g := range batch {
+			if g.Status != GameStatusFinished && g.Status != GameStatusCancelled {
+				continue
+			}
+			if g.FinishedAt == nil || !g.FinishedAt.Before(cutoff) {
+				continue
+			}
+			out = append(out, g)
+		}
+		if len(batch) < pageSize {
+			break
+		}
+		page++
+	}
+	return out, nil
+}
+
+// DeleteGame removes the game and every referencing row (memberships,
+// applications, invites, runtime_records, player_mappings) via the
+// `ON DELETE CASCADE` constraints declared in `00001_init.sql`.
+// Idempotent: returns nil when no game matches.
+//
+// Phase 14 introduces this method for the dev-sandbox bootstrap so a
+// terminal "Dev Sandbox" tile from a previous local-dev session can
+// be scrubbed before a fresh game spawns. Production callers must
+// stay on the regular cancel / finish lifecycle — `DeleteGame` is
+// destructive and bypasses the cascade-notification machinery.
+func (s *Service) DeleteGame(ctx context.Context, gameID uuid.UUID) error {
+	if err := s.deps.Store.DeleteGame(ctx, gameID); err != nil {
+		return err
+	}
+	s.deps.Cache.RemoveGame(gameID)
+	return nil
+}
+
 // State-machine transition handlers below take the same shape: load the
 // game (cache or store), check owner, validate the current status, run
 // the transition write, refresh the cache, optionally tell the runtime
@@ -423,9 +477,43 @@ func (s *Service) transition(ctx context.Context, callerUserID *uuid.UUID, calle
 			return updated, fmt.Errorf("post-commit %s: %w", rule.Reason, err)
 		}
 	}
+	s.emitGameLifecycleMail(ctx, updated, callerIsAdmin, rule)
 	return updated, nil
 }
 
+// emitGameLifecycleMail asks the diplomail publisher to drop a
+// system-mail entry whenever a state change is user-visible. Only
+// the `paused` and `cancelled` transitions emit mail today (the spec
+// names them explicitly); `running`/`finished`/etc. are signalled by
+// other channels and do not need a durable inbox entry.
+func (s *Service) emitGameLifecycleMail(ctx context.Context, game GameRecord, callerIsAdmin bool, rule transitionRule) {
+	var kind string
+	switch rule.To {
+	case GameStatusPaused:
+		kind = LifecycleKindGamePaused
+	case GameStatusCancelled:
+		kind = LifecycleKindGameCancelled
+	default:
+		return
+	}
+	actor := "the game owner"
+	if callerIsAdmin {
+		actor = "an administrator"
+	}
+	ev := LifecycleEvent{
+		GameID: game.GameID,
+		Kind:   kind,
+		Actor:  actor,
+		Reason: rule.Reason,
+	}
+	if err := s.deps.Diplomail.PublishLifecycle(ctx, ev); err != nil {
+		s.deps.Logger.Warn("publish lifecycle mail failed",
+			zap.String("game_id", game.GameID.String()),
+			zap.String("kind", kind),
+			zap.Error(err))
+	}
+}
+
 // checkOwner enforces ownership semantics:
 //
 // - callerIsAdmin == true → always allowed (admin force-start, etc.).

backend/internal/lobby/lobby.go

@@ -109,6 +109,8 @@ const (
 	NotificationLobbyRaceNameRegistered = "lobby.race_name.registered"
 	NotificationLobbyRaceNamePending = "lobby.race_name.pending"
 	NotificationLobbyRaceNameExpired = "lobby.race_name.expired"
+	NotificationGameTurnReady = "game.turn.ready"
+	NotificationGamePaused = "game.paused"
 )
 
 // Deps aggregates every collaborator the lobby Service depends on.
@@ -122,6 +124,7 @@ type Deps struct {
 	Cache *Cache
 	Runtime RuntimeGateway
 	Notification NotificationPublisher
+	Diplomail DiplomailPublisher
 	Entitlement EntitlementProvider
 	Policy *Policy
 	Config config.LobbyConfig
@@ -154,6 +157,9 @@ func NewService(deps Deps) (*Service, error) {
 	if deps.Notification == nil {
 		deps.Notification = NewNoopNotificationPublisher(deps.Logger)
 	}
+	if deps.Diplomail == nil {
+		deps.Diplomail = NewNoopDiplomailPublisher(deps.Logger)
+	}
 	if deps.Policy == nil {
 		policy, err := NewPolicy()
 		if err != nil {

backend/internal/lobby/lobby_e2e_test.go

@@ -244,6 +244,70 @@ func TestEndToEndPrivateGameFlow(t *testing.T) {
 	}
 }
 
+// TestDeleteGameCascadesEverything pins the contract the dev-sandbox
+// bootstrap relies on: removing a game wipes every referencing row
+// (memberships, applications, invites, runtime_records,
+// player_mappings) in a single SQL statement. Before this is wired
+// the developer's lobby pile up cancelled tiles between
+// `make rebuild` cycles; with it, every boot starts from a clean
+// slate.
+func TestDeleteGameCascadesEverything(t *testing.T) {
+	db := startPostgres(t)
+	now := time.Now().UTC()
+	clock := func() time.Time { return now }
+	svc := newServiceForTest(t, db, clock, 5)
+
+	owner := uuid.New()
+	seedAccount(t, db, owner)
+	game, err := svc.CreateGame(context.Background(), lobby.CreateGameInput{
+		OwnerUserID:         &owner,
+		Visibility:          lobby.VisibilityPrivate,
+		GameName:            "Doomed",
+		MinPlayers:          1,
+		MaxPlayers:          4,
+		StartGapHours:       1,
+		StartGapPlayers:     1,
+		EnrollmentEndsAt:    now.Add(time.Hour),
+		TurnSchedule:        "0 0 * * *",
+		TargetEngineVersion: "1.0.0",
+	})
+	if err != nil {
+		t.Fatalf("create game: %v", err)
+	}
+	if _, err := svc.OpenEnrollment(context.Background(), &owner, false, game.GameID); err != nil {
+		t.Fatalf("open enrollment: %v", err)
+	}
+	if _, err := svc.InsertMembershipDirect(context.Background(), lobby.InsertMembershipDirectInput{
+		GameID:   game.GameID,
+		UserID:   owner,
+		RaceName: "Owner",
+	}); err != nil {
+		t.Fatalf("insert membership: %v", err)
+	}
+
+	if err := svc.DeleteGame(context.Background(), game.GameID); err != nil {
+		t.Fatalf("delete game: %v", err)
+	}
+
+	// Verify cascade: the game must be gone, ListMyGames must drop
+	// it, and re-deleting the same id is a no-op.
+	if _, err := svc.GetGame(context.Background(), game.GameID); !errors.Is(err, lobby.ErrNotFound) {
+		t.Fatalf("get after delete: err = %v, want ErrNotFound", err)
+	}
+	games, err := svc.ListMyGames(context.Background(), owner)
+	if err != nil {
+		t.Fatalf("list my games: %v", err)
+	}
+	for _, g := range games {
+		if g.GameID == game.GameID {
+			t.Fatalf("ListMyGames still lists the deleted game")
+		}
+	}
+	if err := svc.DeleteGame(context.Background(), game.GameID); err != nil {
+		t.Fatalf("delete idempotent: %v", err)
+	}
+}
+
 func TestEndToEndPublicGameApplicationApproval(t *testing.T) {
 	db := startPostgres(t)
 	now := time.Now().UTC()

backend/internal/lobby/membership_direct.go

@@ -0,0 +1,96 @@
+package lobby
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/google/uuid"
+)
+
+// InsertMembershipDirectInput is the parameter struct for
+// Service.InsertMembershipDirect.
+type InsertMembershipDirectInput struct {
+	GameID   uuid.UUID
+	UserID   uuid.UUID
+	RaceName string
+}
+
+// InsertMembershipDirect grants a membership to userID inside gameID
+// bypassing the application/approval flow. It performs the same DB
+// writes as ApproveApplication: the per-game race-name reservation
+// row plus the membership row, and refreshes the in-memory caches.
+//
+// The method is intended for boot-time provisioning by
+// `backend/internal/devsandbox` and similar trusted callers. It is
+// not exposed through any HTTP handler. The caller must guarantee
+// game.Status == GameStatusEnrollmentOpen — the function returns
+// ErrConflict otherwise — and that the race-name policy and
+// canonical-key invariants are honoured (the implementation reuses
+// the lobby's own Policy and assertRaceNameAvailable so a duplicate
+// or unsuitable name still fails).
+//
+// Idempotency: if a membership for (GameID, UserID) already exists
+// the function returns the existing row without modifying state.
+// This makes the helper safe to call on every backend boot from
+// devsandbox.Bootstrap.
+func (s *Service) InsertMembershipDirect(ctx context.Context, in InsertMembershipDirectInput) (Membership, error) {
+	displayName, err := ValidateDisplayName(in.RaceName)
+	if err != nil {
+		return Membership{}, err
+	}
+	game, err := s.GetGame(ctx, in.GameID)
+	if err != nil {
+		return Membership{}, err
+	}
+	if game.Status != GameStatusEnrollmentOpen {
+		return Membership{}, fmt.Errorf("%w: game status is %q, want enrollment_open", ErrConflict, game.Status)
+	}
+	canonical, err := s.deps.Policy.Canonical(displayName)
+	if err != nil {
+		return Membership{}, err
+	}
+	existing, err := s.deps.Store.ListMembershipsForGame(ctx, in.GameID)
+	if err != nil {
+		return Membership{}, err
+	}
+	for _, m := range existing {
+		if m.UserID == in.UserID && m.Status == MembershipStatusActive {
+			return m, nil
+		}
+	}
+	if err := s.assertRaceNameAvailable(ctx, canonical, in.UserID, in.GameID); err != nil {
+		return Membership{}, err
+	}
+	now := s.deps.Now().UTC()
+	if _, err := s.deps.Store.InsertRaceName(ctx, raceNameInsert{
+		Name:        displayName,
+		Canonical:   canonical,
+		Status:      RaceNameStatusReservation,
+		OwnerUserID: in.UserID,
+		GameID:      in.GameID,
+		ReservedAt:  &now,
+	}); err != nil {
+		return Membership{}, err
+	}
+	membership, err := s.deps.Store.InsertMembership(ctx, membershipInsert{
+		MembershipID: uuid.New(),
+		GameID:       in.GameID,
+		UserID:       in.UserID,
+		RaceName:     displayName,
+		CanonicalKey: canonical,
+	})
+	if err != nil {
+		_ = s.deps.Store.DeleteRaceName(ctx, canonical, in.GameID)
+		return Membership{}, err
+	}
+	s.deps.Cache.PutMembership(membership)
+	s.deps.Cache.PutRaceName(RaceNameEntry{
+		Name:        displayName,
+		Canonical:   canonical,
+		Status:      RaceNameStatusReservation,
+		OwnerUserID: in.UserID,
+		GameID:      in.GameID,
+		ReservedAt:  &now,
+	})
+	return membership, nil
+}

backend/internal/lobby/memberships.go

@@ -76,6 +76,7 @@ func (s *Service) AdminBanMember(ctx context.Context, gameID, userID uuid.UUID,
 			zap.String("membership_id", updated.MembershipID.String()),
 			zap.Error(pubErr))
 	}
+	s.emitMembershipLifecycleMail(ctx, updated, MembershipStatusBlocked, true, reason)
 	_ = game
 	return updated, nil
 }
@@ -142,9 +143,44 @@ func (s *Service) changeMembershipStatus(
 			zap.String("kind", notificationKind),
 			zap.Error(pubErr))
 	}
+	s.emitMembershipLifecycleMail(ctx, updated, newStatus, callerIsAdmin, "")
 	return updated, nil
 }
 
+// emitMembershipLifecycleMail asks the diplomail publisher to drop a
+// durable explanation into the kicked player's inbox. The mail
+// survives the membership row going to `removed` / `blocked` so the
+// player keeps read access to it (soft-access rule, item 8).
+func (s *Service) emitMembershipLifecycleMail(ctx context.Context, membership Membership, newStatus string, callerIsAdmin bool, reason string) {
+	var kind string
+	switch newStatus {
+	case MembershipStatusRemoved:
+		kind = LifecycleKindMembershipRemoved
+	case MembershipStatusBlocked:
+		kind = LifecycleKindMembershipBlocked
+	default:
+		return
+	}
+	actor := "the game owner"
+	if callerIsAdmin {
+		actor = "an administrator"
+	}
+	target := membership.UserID
+	ev := LifecycleEvent{
+		GameID:     membership.GameID,
+		Kind:       kind,
+		Actor:      actor,
+		Reason:     reason,
+		TargetUser: &target,
+	}
+	if err := s.deps.Diplomail.PublishLifecycle(ctx, ev); err != nil {
+		s.deps.Logger.Warn("publish membership lifecycle mail failed",
+			zap.String("membership_id", membership.MembershipID.String()),
+			zap.String("kind", kind),
+			zap.Error(err))
+	}
+}
+
 func (s *Service) canManageMembership(game GameRecord, membership Membership, callerUserID *uuid.UUID, allowSelf bool) bool {
 	if game.Visibility == VisibilityPublic {
 		// Public-game membership management is admin-only.

backend/internal/lobby/runtime_hooks.go

@@ -30,12 +30,14 @@ func (s *Service) OnRuntimeSnapshot(ctx context.Context, gameID uuid.UUID, snaps
 	if err != nil {
 		return err
 	}
+	prevTurn := game.RuntimeSnapshot.CurrentTurn
 	merged := mergeRuntimeSnapshot(game.RuntimeSnapshot, snapshot)
 	now := s.deps.Now().UTC()
 	updated, err := s.deps.Store.UpdateGameRuntimeSnapshot(ctx, gameID, merged, now)
 	if err != nil {
 		return err
 	}
+	transitionedToPaused := false
 	if next, transition := nextStatusFromSnapshot(updated.Status, snapshot); transition {
 		switch next {
 		case GameStatusFinished:
@@ -52,12 +54,115 @@ func (s *Service) OnRuntimeSnapshot(ctx context.Context, gameID uuid.UUID, snaps
 				return err
 			}
 			updated = rec
+			if next == GameStatusPaused {
+				transitionedToPaused = true
+			}
 		}
 	}
 	s.deps.Cache.PutGame(updated)
+	if merged.CurrentTurn > prevTurn {
+		s.publishTurnReady(ctx, gameID, merged.CurrentTurn)
+	}
+	if transitionedToPaused {
+		s.publishGamePaused(ctx, gameID, merged.CurrentTurn, snapshot.RuntimeStatus)
+	}
 	return nil
 }
 
+// publishTurnReady fans out a `game.turn.ready` notification to every
+// active member of the game once the engine reports a new
+// `current_turn`. The intent is best-effort: a publisher failure is
+// logged at warn level (matching the rest of OnRuntimeSnapshot's
+// notification calls) and does not abort the snapshot bookkeeping.
+// Idempotency is anchored on (game_id, turn), so a duplicate snapshot
+// for the same turn collapses into a single notification at the
+// notification.Submit boundary.
+func (s *Service) publishTurnReady(ctx context.Context, gameID uuid.UUID, turn int32) {
+	memberships, err := s.deps.Store.ListMembershipsForGame(ctx, gameID)
+	if err != nil {
+		s.deps.Logger.Warn("turn-ready notification: list memberships failed",
+			zap.String("game_id", gameID.String()),
+			zap.Int32("turn", turn),
+			zap.Error(err))
+		return
+	}
+	recipients := make([]uuid.UUID, 0, len(memberships))
+	for _, m := range memberships {
+		if m.Status != MembershipStatusActive {
+			continue
+		}
+		recipients = append(recipients, m.UserID)
+	}
+	if len(recipients) == 0 {
+		return
+	}
+	intent := LobbyNotification{
+		Kind:           NotificationGameTurnReady,
+		IdempotencyKey: fmt.Sprintf("turn-ready:%s:%d", gameID, turn),
+		Recipients:     recipients,
+		Payload: map[string]any{
+			"game_id": gameID.String(),
+			"turn":    turn,
+		},
+	}
+	if pubErr := s.deps.Notification.PublishLobbyEvent(ctx, intent); pubErr != nil {
+		s.deps.Logger.Warn("turn-ready notification failed",
+			zap.String("game_id", gameID.String()),
+			zap.Int32("turn", turn),
+			zap.Error(pubErr))
+	}
+}
+
+// publishGamePaused fans out a `game.paused` notification to every
+// active member of the game when the lobby flips the game to
+// `paused` in reaction to a runtime snapshot (typically a failed
+// turn generation). The intent is best-effort: a publisher failure
+// is logged at warn level and does not abort the snapshot
+// bookkeeping. Idempotency is anchored on (game_id, turn) so a
+// repeated `generation_failed` snapshot for the same turn collapses
+// into a single notification at the notification.Submit boundary.
+//
+// reason carries the raw runtime status that triggered the pause
+// (`engine_unreachable` / `generation_failed`); the UI displays a
+// status-agnostic banner today but the payload is preserved so a
+// future revision of the order tab can differentiate.
+func (s *Service) publishGamePaused(ctx context.Context, gameID uuid.UUID, turn int32, reason string) {
+	memberships, err := s.deps.Store.ListMembershipsForGame(ctx, gameID)
+	if err != nil {
+		s.deps.Logger.Warn("game-paused notification: list memberships failed",
+			zap.String("game_id", gameID.String()),
+			zap.Int32("turn", turn),
+			zap.Error(err))
+		return
+	}
+	recipients := make([]uuid.UUID, 0, len(memberships))
+	for _, m := range memberships {
+		if m.Status != MembershipStatusActive {
+			continue
+		}
+		recipients = append(recipients, m.UserID)
+	}
+	if len(recipients) == 0 {
+		return
+	}
+	intent := LobbyNotification{
+		Kind:           NotificationGamePaused,
+		IdempotencyKey: fmt.Sprintf("paused:%s:%d", gameID, turn),
+		Recipients:     recipients,
+		Payload: map[string]any{
+			"game_id": gameID.String(),
+			"turn":    turn,
+			"reason":  reason,
+		},
+	}
+	if pubErr := s.deps.Notification.PublishLobbyEvent(ctx, intent); pubErr != nil {
+		s.deps.Logger.Warn("game-paused notification failed",
+			zap.String("game_id", gameID.String()),
+			zap.Int32("turn", turn),
+			zap.Error(pubErr))
+	}
+}
+
 // OnGameFinished completes the game lifecycle: marks the game as
 // `finished`, evaluates capable-finish per active member, and
 // transitions reservation rows to either `pending_registration`
@@ -230,13 +335,28 @@ func mergeRuntimeSnapshot(prev, next RuntimeSnapshot) RuntimeSnapshot {
 // nextStatusFromSnapshot maps the runtime-reported runtime status into
 // a lobby status transition. Returns (next, true) when the lobby
 // status must change; (current, false) otherwise.
+//
+// The map intentionally distinguishes the pre-running boot path
+// (`starting → start_failed`) from the in-flight failure path
+// (`running → paused`). Paused games can be resumed by the admin via
+// the explicit `/resume` transition; the runtime keeps the engine
+// container alive, the scheduler short-circuits ticks while paused,
+// and any user-games command/order is rejected by the order handler
+// with `turn_already_closed` until the game resumes.
 func nextStatusFromSnapshot(currentStatus string, snapshot RuntimeSnapshot) (string, bool) {
 	switch snapshot.RuntimeStatus {
 	case "running":
 		if currentStatus == GameStatusStarting {
 			return GameStatusRunning, true
 		}
-	case "engine_unreachable", "start_failed", "generation_failed":
+	case "engine_unreachable", "generation_failed":
+		if currentStatus == GameStatusStarting {
+			return GameStatusStartFailed, true
+		}
+		if currentStatus == GameStatusRunning {
+			return GameStatusPaused, true
+		}
+	case "start_failed":
 		if currentStatus == GameStatusStarting {
 			return GameStatusStartFailed, true
 		}

backend/internal/lobby/runtime_hooks_test.go

@@ -0,0 +1,207 @@
+package lobby_test
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"galaxy/backend/internal/config"
+	"galaxy/backend/internal/lobby"
+
+	"github.com/google/uuid"
+)
+
+// capturingPublisher records every `LobbyNotification` intent that the
+// lobby service emits, so a test can assert the producer side without
+// running the real notification.Submit pipeline.
+type capturingPublisher struct {
+	mu    sync.Mutex
+	items []lobby.LobbyNotification
+}
+
+func (p *capturingPublisher) PublishLobbyEvent(_ context.Context, ev lobby.LobbyNotification) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.items = append(p.items, ev)
+	return nil
+}
+
+func (p *capturingPublisher) byKind(kind string) []lobby.LobbyNotification {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	out := make([]lobby.LobbyNotification, 0, len(p.items))
+	for _, ev := range p.items {
+		if ev.Kind == kind {
+			out = append(out, ev)
+		}
+	}
+	return out
+}
+
+// newServiceWithPublisher mirrors `newServiceForTest` but lets the
+// caller inject a custom NotificationPublisher; the runtime-hooks
+// emit path needs to observe intents directly.
+func newServiceWithPublisher(t *testing.T, db *sql.DB, now func() time.Time, max int32, publisher lobby.NotificationPublisher) *lobby.Service {
+	t.Helper()
+	store := lobby.NewStore(db)
+	cache := lobby.NewCache()
+	if err := cache.Warm(context.Background(), store); err != nil {
+		t.Fatalf("warm cache: %v", err)
+	}
+	svc, err := lobby.NewService(lobby.Deps{
+		Store:        store,
+		Cache:        cache,
+		Notification: publisher,
+		Entitlement:  stubEntitlement{max: max},
+		Config: config.LobbyConfig{
+			SweeperInterval:        time.Second,
+			PendingRegistrationTTL: time.Hour,
+			InviteDefaultTTL:       time.Hour,
+		},
+		Now: now,
+	})
+	if err != nil {
+		t.Fatalf("new service: %v", err)
+	}
+	return svc
+}
+
+// TestOnRuntimeSnapshotEmitsTurnReady verifies that an engine snapshot
+// advancing `current_turn` fans out a `game.turn.ready` intent to every
+// active member, that the idempotency key is anchored on (game_id, turn),
+// and that a snapshot with the same turn does not re-emit.
+func TestOnRuntimeSnapshotEmitsTurnReady(t *testing.T) {
+	db := startPostgres(t)
+	now := time.Now().UTC()
+	clock := func() time.Time { return now }
+	publisher := &capturingPublisher{}
+	svc := newServiceWithPublisher(t, db, clock, 5, publisher)
+
+	owner := uuid.New()
+	seedAccount(t, db, owner)
+
+	game, err := svc.CreateGame(context.Background(), lobby.CreateGameInput{
+		OwnerUserID:         &owner,
+		Visibility:          lobby.VisibilityPrivate,
+		GameName:            "Turn-Ready Fan-Out",
+		MinPlayers:          1,
+		MaxPlayers:          4,
+		StartGapHours:       1,
+		StartGapPlayers:     1,
+		EnrollmentEndsAt:    now.Add(time.Hour),
+		TurnSchedule:        "0 0 * * *",
+		TargetEngineVersion: "1.0.0",
+	})
+	if err != nil {
+		t.Fatalf("create game: %v", err)
+	}
+	if _, err := svc.OpenEnrollment(context.Background(), &owner, false, game.GameID); err != nil {
+		t.Fatalf("open enrollment: %v", err)
+	}
+
+	// Seed two active members through the store so the test focuses on
+	// the runtime hook, not the membership state machine.
+	store := lobby.NewStore(db)
+	canonicalPolicy, err := lobby.NewPolicy()
+	if err != nil {
+		t.Fatalf("new policy: %v", err)
+	}
+	memberA := uuid.New()
+	memberB := uuid.New()
+	seedAccount(t, db, memberA)
+	seedAccount(t, db, memberB)
+	for i, m := range []uuid.UUID{memberA, memberB} {
+		race := fmt.Sprintf("Race%d", i+1)
+		canonical, err := canonicalPolicy.Canonical(race)
+		if err != nil {
+			t.Fatalf("canonical %q: %v", race, err)
+		}
+		if _, err := db.ExecContext(context.Background(), `
+			INSERT INTO backend.memberships (
+				membership_id, game_id, user_id, race_name, canonical_key, status
+			) VALUES ($1, $2, $3, $4, $5, 'active')
+		`, uuid.New(), game.GameID, m, race, string(canonical)); err != nil {
+			t.Fatalf("seed membership %s: %v", m, err)
+		}
+	}
+	if err := svc.Cache().Warm(context.Background(), store); err != nil {
+		t.Fatalf("re-warm cache: %v", err)
+	}
+	if _, err := svc.ReadyToStart(context.Background(), &owner, false, game.GameID); err != nil {
+		t.Fatalf("ready-to-start: %v", err)
+	}
+	if _, err := svc.Start(context.Background(), &owner, false, game.GameID); err != nil {
+		t.Fatalf("start: %v", err)
+	}
+
+	// First snapshot: prev=0, current_turn=1 → emit on the very first
+	// turn after the engine starts producing.
+	if err := svc.OnRuntimeSnapshot(context.Background(), game.GameID, lobby.RuntimeSnapshot{
+		CurrentTurn:   1,
+		RuntimeStatus: "running",
+	}); err != nil {
+		t.Fatalf("on-runtime-snapshot 1: %v", err)
+	}
+	intents := publisher.byKind(lobby.NotificationGameTurnReady)
+	if len(intents) != 1 {
+		t.Fatalf("after turn 1 want 1 turn-ready intent, got %d", len(intents))
+	}
+	first := intents[0]
+	wantKey := fmt.Sprintf("turn-ready:%s:1", game.GameID)
+	if first.IdempotencyKey != wantKey {
+		t.Errorf("turn 1 idempotency key = %q, want %q", first.IdempotencyKey, wantKey)
+	}
+	if got := first.Payload["turn"]; got != int32(1) {
+		t.Errorf("turn 1 payload turn = %v, want 1", got)
+	}
+	if got := first.Payload["game_id"]; got != game.GameID.String() {
+		t.Errorf("turn 1 payload game_id = %v, want %s", got, game.GameID)
+	}
+	if len(first.Recipients) != 2 {
+		t.Errorf("turn 1 recipients = %d, want 2", len(first.Recipients))
+	}
+	recipientSet := map[uuid.UUID]struct{}{}
+	for _, r := range first.Recipients {
+		recipientSet[r] = struct{}{}
+	}
+	if _, ok := recipientSet[memberA]; !ok {
+		t.Errorf("turn 1 missing memberA in recipients")
+	}
+	if _, ok := recipientSet[memberB]; !ok {
+		t.Errorf("turn 1 missing memberB in recipients")
+	}
+
+	// Same turn re-delivered (duplicate snapshot, gateway replay) must
+	// not re-emit at the lobby layer: prev catches up to merged.
+	if err := svc.OnRuntimeSnapshot(context.Background(), game.GameID, lobby.RuntimeSnapshot{
+		CurrentTurn:   1,
+		RuntimeStatus: "running",
+	}); err != nil {
+		t.Fatalf("on-runtime-snapshot 1 replay: %v", err)
+	}
+	if got := len(publisher.byKind(lobby.NotificationGameTurnReady)); got != 1 {
+		t.Fatalf("after duplicate turn 1 want 1 intent, got %d", got)
+	}
+
+	// Next turn advances → second emit with key anchored on turn 2.
+	if err := svc.OnRuntimeSnapshot(context.Background(), game.GameID, lobby.RuntimeSnapshot{
+		CurrentTurn:   2,
+		RuntimeStatus: "running",
+	}); err != nil {
+		t.Fatalf("on-runtime-snapshot 2: %v", err)
+	}
+	intents = publisher.byKind(lobby.NotificationGameTurnReady)
+	if len(intents) != 2 {
+		t.Fatalf("after turn 2 want 2 turn-ready intents, got %d", len(intents))
+	}
+	wantKey2 := fmt.Sprintf("turn-ready:%s:2", game.GameID)
+	if intents[1].IdempotencyKey != wantKey2 {
+		t.Errorf("turn 2 idempotency key = %q, want %q", intents[1].IdempotencyKey, wantKey2)
+	}
+	if got := intents[1].Payload["turn"]; got != int32(2) {
+		t.Errorf("turn 2 payload turn = %v, want 2", got)
+	}
+}

backend/internal/lobby/runtime_hooks_unit_test.go

@@ -0,0 +1,127 @@
+package lobby
+
+import "testing"
+
+// TestNextStatusFromSnapshot covers the pure status-mapping function
+// that drives `OnRuntimeSnapshot`'s lifecycle transitions. The Phase
+// 25 contribution is the `running → paused` branch on
+// `engine_unreachable` / `generation_failed`: the order handler relies
+// on the `paused` game status to reject late submits with
+// `turn_already_closed`.
+func TestNextStatusFromSnapshot(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name          string
+		currentStatus string
+		runtimeStatus string
+		wantStatus    string
+		wantTransit   bool
+	}{
+		{
+			name:          "starting then running flips to running",
+			currentStatus: GameStatusStarting,
+			runtimeStatus: "running",
+			wantStatus:    GameStatusRunning,
+			wantTransit:   true,
+		},
+		{
+			name:          "running on running snapshot does not transit",
+			currentStatus: GameStatusRunning,
+			runtimeStatus: "running",
+			wantStatus:    GameStatusRunning,
+			wantTransit:   false,
+		},
+		{
+			name:          "starting then engine_unreachable flips to start_failed",
+			currentStatus: GameStatusStarting,
+			runtimeStatus: "engine_unreachable",
+			wantStatus:    GameStatusStartFailed,
+			wantTransit:   true,
+		},
+		{
+			name:          "starting then generation_failed flips to start_failed",
+			currentStatus: GameStatusStarting,
+			runtimeStatus: "generation_failed",
+			wantStatus:    GameStatusStartFailed,
+			wantTransit:   true,
+		},
+		{
+			name:          "running then engine_unreachable flips to paused",
+			currentStatus: GameStatusRunning,
+			runtimeStatus: "engine_unreachable",
+			wantStatus:    GameStatusPaused,
+			wantTransit:   true,
+		},
+		{
+			name:          "running then generation_failed flips to paused",
+			currentStatus: GameStatusRunning,
+			runtimeStatus: "generation_failed",
+			wantStatus:    GameStatusPaused,
+			wantTransit:   true,
+		},
+		{
+			name:          "paused stays paused on repeated failed snapshot",
+			currentStatus: GameStatusPaused,
+			runtimeStatus: "generation_failed",
+			wantStatus:    GameStatusPaused,
+			wantTransit:   false,
+		},
+		{
+			name:          "starting then start_failed flips to start_failed",
+			currentStatus: GameStatusStarting,
+			runtimeStatus: "start_failed",
+			wantStatus:    GameStatusStartFailed,
+			wantTransit:   true,
+		},
+		{
+			name:          "running ignores start_failed",
+			currentStatus: GameStatusRunning,
+			runtimeStatus: "start_failed",
+			wantStatus:    GameStatusRunning,
+			wantTransit:   false,
+		},
+		{
+			name:          "running on finished flips to finished",
+			currentStatus: GameStatusRunning,
+			runtimeStatus: "finished",
+			wantStatus:    GameStatusFinished,
+			wantTransit:   true,
+		},
+		{
+			name:          "finished stays finished on finished snapshot",
+			currentStatus: GameStatusFinished,
+			runtimeStatus: "finished",
+			wantStatus:    GameStatusFinished,
+			wantTransit:   false,
+		},
+		{
+			name:          "cancelled stays cancelled on finished snapshot",
+			currentStatus: GameStatusCancelled,
+			runtimeStatus: "finished",
+			wantStatus:    GameStatusCancelled,
+			wantTransit:   false,
+		},
+		{
+			name:          "paused on stopped snapshot flips to finished",
+			currentStatus: GameStatusPaused,
+			runtimeStatus: "stopped",
+			wantStatus:    GameStatusFinished,
+			wantTransit:   true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got, transit := nextStatusFromSnapshot(tt.currentStatus, RuntimeSnapshot{
+				RuntimeStatus: tt.runtimeStatus,
+			})
+			if got != tt.wantStatus {
+				t.Errorf("status = %q, want %q", got, tt.wantStatus)
+			}
+			if transit != tt.wantTransit {
+				t.Errorf("transit = %v, want %v", transit, tt.wantTransit)
+			}
+		})
+	}
+}

backend/internal/lobby/store.go

@@ -232,6 +232,22 @@ func (s *Store) ListMyGames(ctx context.Context, userID uuid.UUID) ([]GameRecord
 	return modelsToGameRecords(rows)
 }
 
+// DeleteGame removes the row at gameID. Cascades through every
+// referencing table (memberships / applications / invites /
+// runtime_records / player_mappings — all declared with ON DELETE
+// CASCADE in `00001_init.sql`). Idempotent: returns nil when no row
+// matches. Used by the dev-sandbox bootstrap to scrub terminal
+// games on every backend boot so the developer's lobby never piles
+// up cancelled tiles.
+func (s *Store) DeleteGame(ctx context.Context, gameID uuid.UUID) error {
+	g := table.Games
+	stmt := g.DELETE().WHERE(g.GameID.EQ(postgres.UUID(gameID)))
+	if _, err := stmt.ExecContext(ctx, s.db); err != nil {
+		return fmt.Errorf("lobby store: delete game %s: %w", gameID, err)
+	}
+	return nil
+}
+
 // gameUpdate is the parameter struct for UpdateGame. Nil pointers leave
 // the corresponding column alone.
 type gameUpdate struct {

backend/internal/notification/catalog.go

@@ -17,6 +17,9 @@ const (
 	KindRuntimeImagePullFailed = "runtime.image_pull_failed"
 	KindRuntimeContainerStartFailed = "runtime.container_start_failed"
 	KindRuntimeStartConfigInvalid = "runtime.start_config_invalid"
+	KindGameTurnReady = "game.turn.ready"
+	KindGamePaused = "game.paused"
+	KindDiplomailReceived = "diplomail.message.received"
 )
 
 // CatalogEntry describes the per-kind delivery policy: which channels
@@ -95,6 +98,15 @@ var catalog = map[string]CatalogEntry{
 		Admin: true,
 		MailTemplateID: KindRuntimeStartConfigInvalid,
 	},
+	KindGameTurnReady: {
+		Channels: []string{ChannelPush},
+	},
+	KindGamePaused: {
+		Channels: []string{ChannelPush},
+	},
+	KindDiplomailReceived: {
+		Channels: []string{ChannelPush},
+	},
 }
 
 // LookupCatalog returns the per-kind policy and a boolean reporting
@@ -123,5 +135,8 @@ func SupportedKinds() []string {
 		KindRuntimeImagePullFailed,
 		KindRuntimeContainerStartFailed,
 		KindRuntimeStartConfigInvalid,
+		KindGameTurnReady,
+		KindGamePaused,
+		KindDiplomailReceived,
 	}
 }

backend/internal/notification/catalog_test.go

@@ -39,6 +39,9 @@ func TestCatalogChannels(t *testing.T) {
 		KindRuntimeImagePullFailed:      {ChannelEmail},
 		KindRuntimeContainerStartFailed: {ChannelEmail},
 		KindRuntimeStartConfigInvalid:   {ChannelEmail},
+		KindGameTurnReady:               {ChannelPush},
+		KindGamePaused:                  {ChannelPush},
+		KindDiplomailReceived:           {ChannelPush},
 	}
 	for kind, want := range expect {
 		entry, ok := LookupCatalog(kind)

backend/internal/notification/events_test.go

@@ -9,9 +9,37 @@ import (
 	"github.com/google/uuid"
 )
 
+// jsonFriendlyKinds lists catalog kinds whose payload is small and
+// stable enough that the gateway-bound encoding stays JSON instead of
+// FlatBuffers. The default for new producers is still FB; declaring a
+// kind here is a deliberate decision baked into the build target's
+// payload contract.
+//
+// `game.turn.ready` ships `{game_id, turn}` only, the UI parses it
+// inline in `routes/games/[id]/+layout.svelte` (Phase 24), and no
+// other consumer reads the payload — adopting the FB encoder would
+// require a new TS notification stub set and the regen tooling for
+// `pkg/schema/fbs/notification.fbs` without buying anything.
+//
+// `game.paused` (Phase 25) follows the same JSON-friendly contract:
+// payload is `{game_id, turn, reason}` consumed by the same in-game
+// shell layout, so there is no value in dragging a FB schema in for
+// one consumer.
+//
+// `diplomail.message.received` (Stage A) carries the message metadata
+// plus an unread-count snapshot. Stage A intentionally ships the
+// payload as JSON so the diplomail UI can iterate on the contract
+// without a FB schema dance; a later stage can promote it.
+var jsonFriendlyKinds = map[string]bool{
+	KindGameTurnReady:     true,
+	KindGamePaused:        true,
+	KindDiplomailReceived: true,
+}
+
 // TestBuildClientPushEventCoversCatalog asserts that every catalog kind
-// returns a typed FB event (preMarshaledEvent) and that an unknown kind
+// is exercised by this test, that FB-typed kinds return a
-// falls through to the JSON safety net.
+// `preMarshaledEvent`, and that JSON-friendly kinds (see
+// `jsonFriendlyKinds` above) return a `push.JSONEvent`.
 func TestBuildClientPushEventCoversCatalog(t *testing.T) {
 	t.Parallel()
 
@@ -57,6 +85,26 @@ func TestBuildClientPushEventCoversCatalog(t *testing.T) {
 			"game_id": gameID.String(),
 			"reason":  "missing engine version",
 		}},
+		{"game turn ready", KindGameTurnReady, map[string]any{
+			"game_id": gameID.String(),
+			"turn":    int32(7),
+		}},
+		{"game paused", KindGamePaused, map[string]any{
+			"game_id": gameID.String(),
+			"turn":    int32(7),
+			"reason":  "generation_failed",
+		}},
+		{"diplomail message received", KindDiplomailReceived, map[string]any{
+			"message_id":   gameID.String(),
+			"game_id":      gameID.String(),
+			"kind":         "personal",
+			"sender_kind":  "player",
+			"subject":      "Trade deal",
+			"preview":      "Care to talk gas mining?",
+			"preview_lang": "en",
+			"unread_total": 3,
+			"unread_game":  1,
+		}},
 	}
 
 	seenKinds := map[string]bool{}
@@ -78,8 +126,10 @@ func TestBuildClientPushEventCoversCatalog(t *testing.T) {
 			if len(bytes) == 0 {
 				t.Fatalf("Marshal returned empty bytes")
 			}
-			if _, isJSON := event.(push.JSONEvent); isJSON {
+			_, isJSON := event.(push.JSONEvent)
-				t.Fatalf("expected typed FB event for %s, got JSONEvent", tt.kind)
+			wantJSON := jsonFriendlyKinds[tt.kind]
+			if isJSON != wantJSON {
+				t.Fatalf("kind %s: JSONEvent=%v, want JSONEvent=%v", tt.kind, isJSON, wantJSON)
 			}
 		})
 		seenKinds[tt.kind] = true

backend/internal/postgres/jet/backend/model/diplomail_messages.go

@@ -0,0 +1,29 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package model
+
+import (
+	"github.com/google/uuid"
+	"time"
+)
+
+type DiplomailMessages struct {
+	MessageID      uuid.UUID `sql:"primary_key"`
+	GameID         uuid.UUID
+	GameName       string
+	Kind           string
+	SenderKind     string
+	SenderUserID   *uuid.UUID
+	SenderUsername *string
+	SenderIP       string
+	Subject        string
+	Body           string
+	BodyLang       string
+	BroadcastScope string
+	CreatedAt      time.Time
+}

backend/internal/postgres/jet/backend/model/diplomail_recipients.go

@@ -0,0 +1,30 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package model
+
+import (
+	"github.com/google/uuid"
+	"time"
+)
+
+type DiplomailRecipients struct {
+	RecipientID                uuid.UUID `sql:"primary_key"`
+	MessageID                  uuid.UUID
+	GameID                     uuid.UUID
+	UserID                     uuid.UUID
+	RecipientUserName          string
+	RecipientRaceName          *string
+	RecipientPreferredLanguage string
+	AvailableAt                *time.Time
+	TranslationAttempts        int32
+	NextTranslationAttemptAt   *time.Time
+	DeliveredAt                *time.Time
+	ReadAt                     *time.Time
+	DeletedAt                  *time.Time
+	NotifiedAt                 *time.Time
+}

backend/internal/postgres/jet/backend/model/diplomail_translations.go

@@ -0,0 +1,23 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package model
+
+import (
+	"github.com/google/uuid"
+	"time"
+)
+
+type DiplomailTranslations struct {
+	TranslationID     uuid.UUID `sql:"primary_key"`
+	MessageID         uuid.UUID
+	TargetLang        string
+	TranslatedSubject string
+	TranslatedBody    string
+	Translator        string
+	TranslatedAt      time.Time
+}

backend/internal/postgres/jet/backend/table/diplomail_messages.go

@@ -0,0 +1,114 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package table
+
+import (
+	"github.com/go-jet/jet/v2/postgres"
+)
+
+var DiplomailMessages = newDiplomailMessagesTable("backend", "diplomail_messages", "")
+
+type diplomailMessagesTable struct {
+	postgres.Table
+
+	// Columns
+	MessageID      postgres.ColumnString
+	GameID         postgres.ColumnString
+	GameName       postgres.ColumnString
+	Kind           postgres.ColumnString
+	SenderKind     postgres.ColumnString
+	SenderUserID   postgres.ColumnString
+	SenderUsername postgres.ColumnString
+	SenderIP       postgres.ColumnString
+	Subject        postgres.ColumnString
+	Body           postgres.ColumnString
+	BodyLang       postgres.ColumnString
+	BroadcastScope postgres.ColumnString
+	CreatedAt      postgres.ColumnTimestampz
+
+	AllColumns     postgres.ColumnList
+	MutableColumns postgres.ColumnList
+	DefaultColumns postgres.ColumnList
+}
+
+type DiplomailMessagesTable struct {
+	diplomailMessagesTable
+
+	EXCLUDED diplomailMessagesTable
+}
+
+// AS creates new DiplomailMessagesTable with assigned alias
+func (a DiplomailMessagesTable) AS(alias string) *DiplomailMessagesTable {
+	return newDiplomailMessagesTable(a.SchemaName(), a.TableName(), alias)
+}
+
+// Schema creates new DiplomailMessagesTable with assigned schema name
+func (a DiplomailMessagesTable) FromSchema(schemaName string) *DiplomailMessagesTable {
+	return newDiplomailMessagesTable(schemaName, a.TableName(), a.Alias())
+}
+
+// WithPrefix creates new DiplomailMessagesTable with assigned table prefix
+func (a DiplomailMessagesTable) WithPrefix(prefix string) *DiplomailMessagesTable {
+	return newDiplomailMessagesTable(a.SchemaName(), prefix+a.TableName(), a.TableName())
+}
+
+// WithSuffix creates new DiplomailMessagesTable with assigned table suffix
+func (a DiplomailMessagesTable) WithSuffix(suffix string) *DiplomailMessagesTable {
+	return newDiplomailMessagesTable(a.SchemaName(), a.TableName()+suffix, a.TableName())
+}
+
+func newDiplomailMessagesTable(schemaName, tableName, alias string) *DiplomailMessagesTable {
+	return &DiplomailMessagesTable{
+		diplomailMessagesTable: newDiplomailMessagesTableImpl(schemaName, tableName, alias),
+		EXCLUDED:               newDiplomailMessagesTableImpl("", "excluded", ""),
+	}
+}
+
+func newDiplomailMessagesTableImpl(schemaName, tableName, alias string) diplomailMessagesTable {
+	var (
+		MessageIDColumn      = postgres.StringColumn("message_id")
+		GameIDColumn         = postgres.StringColumn("game_id")
+		GameNameColumn       = postgres.StringColumn("game_name")
+		KindColumn           = postgres.StringColumn("kind")
+		SenderKindColumn     = postgres.StringColumn("sender_kind")
+		SenderUserIDColumn   = postgres.StringColumn("sender_user_id")
+		SenderUsernameColumn = postgres.StringColumn("sender_username")
+		SenderIPColumn       = postgres.StringColumn("sender_ip")
+		SubjectColumn        = postgres.StringColumn("subject")
+		BodyColumn           = postgres.StringColumn("body")
+		BodyLangColumn       = postgres.StringColumn("body_lang")
+		BroadcastScopeColumn = postgres.StringColumn("broadcast_scope")
+		CreatedAtColumn      = postgres.TimestampzColumn("created_at")
+		allColumns           = postgres.ColumnList{MessageIDColumn, GameIDColumn, GameNameColumn, KindColumn, SenderKindColumn, SenderUserIDColumn, SenderUsernameColumn, SenderIPColumn, SubjectColumn, BodyColumn, BodyLangColumn, BroadcastScopeColumn, CreatedAtColumn}
+		mutableColumns       = postgres.ColumnList{GameIDColumn, GameNameColumn, KindColumn, SenderKindColumn, SenderUserIDColumn, SenderUsernameColumn, SenderIPColumn, SubjectColumn, BodyColumn, BodyLangColumn, BroadcastScopeColumn, CreatedAtColumn}
+		defaultColumns       = postgres.ColumnList{SenderIPColumn, SubjectColumn, BodyLangColumn, BroadcastScopeColumn, CreatedAtColumn}
+	)
+
+	return diplomailMessagesTable{
+		Table: postgres.NewTable(schemaName, tableName, alias, allColumns...),
+
+		//Columns
+		MessageID:      MessageIDColumn,
+		GameID:         GameIDColumn,
+		GameName:       GameNameColumn,
+		Kind:           KindColumn,
+		SenderKind:     SenderKindColumn,
+		SenderUserID:   SenderUserIDColumn,
+		SenderUsername: SenderUsernameColumn,
+		SenderIP:       SenderIPColumn,
+		Subject:        SubjectColumn,
+		Body:           BodyColumn,
+		BodyLang:       BodyLangColumn,
+		BroadcastScope: BroadcastScopeColumn,
+		CreatedAt:      CreatedAtColumn,
+
+		AllColumns:     allColumns,
+		MutableColumns: mutableColumns,
+		DefaultColumns: defaultColumns,
+	}
+}

backend/internal/postgres/jet/backend/table/diplomail_recipients.go

@@ -0,0 +1,117 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package table
+
+import (
+	"github.com/go-jet/jet/v2/postgres"
+)
+
+var DiplomailRecipients = newDiplomailRecipientsTable("backend", "diplomail_recipients", "")
+
+type diplomailRecipientsTable struct {
+	postgres.Table
+
+	// Columns
+	RecipientID                postgres.ColumnString
+	MessageID                  postgres.ColumnString
+	GameID                     postgres.ColumnString
+	UserID                     postgres.ColumnString
+	RecipientUserName          postgres.ColumnString
+	RecipientRaceName          postgres.ColumnString
+	RecipientPreferredLanguage postgres.ColumnString
+	AvailableAt                postgres.ColumnTimestampz
+	TranslationAttempts        postgres.ColumnInteger
+	NextTranslationAttemptAt   postgres.ColumnTimestampz
+	DeliveredAt                postgres.ColumnTimestampz
+	ReadAt                     postgres.ColumnTimestampz
+	DeletedAt                  postgres.ColumnTimestampz
+	NotifiedAt                 postgres.ColumnTimestampz
+
+	AllColumns     postgres.ColumnList
+	MutableColumns postgres.ColumnList
+	DefaultColumns postgres.ColumnList
+}
+
+type DiplomailRecipientsTable struct {
+	diplomailRecipientsTable
+
+	EXCLUDED diplomailRecipientsTable
+}
+
+// AS creates new DiplomailRecipientsTable with assigned alias
+func (a DiplomailRecipientsTable) AS(alias string) *DiplomailRecipientsTable {
+	return newDiplomailRecipientsTable(a.SchemaName(), a.TableName(), alias)
+}
+
+// Schema creates new DiplomailRecipientsTable with assigned schema name
+func (a DiplomailRecipientsTable) FromSchema(schemaName string) *DiplomailRecipientsTable {
+	return newDiplomailRecipientsTable(schemaName, a.TableName(), a.Alias())
+}
+
+// WithPrefix creates new DiplomailRecipientsTable with assigned table prefix
+func (a DiplomailRecipientsTable) WithPrefix(prefix string) *DiplomailRecipientsTable {
+	return newDiplomailRecipientsTable(a.SchemaName(), prefix+a.TableName(), a.TableName())
+}
+
+// WithSuffix creates new DiplomailRecipientsTable with assigned table suffix
+func (a DiplomailRecipientsTable) WithSuffix(suffix string) *DiplomailRecipientsTable {
+	return newDiplomailRecipientsTable(a.SchemaName(), a.TableName()+suffix, a.TableName())
+}
+
+func newDiplomailRecipientsTable(schemaName, tableName, alias string) *DiplomailRecipientsTable {
+	return &DiplomailRecipientsTable{
+		diplomailRecipientsTable: newDiplomailRecipientsTableImpl(schemaName, tableName, alias),
+		EXCLUDED:                 newDiplomailRecipientsTableImpl("", "excluded", ""),
+	}
+}
+
+func newDiplomailRecipientsTableImpl(schemaName, tableName, alias string) diplomailRecipientsTable {
+	var (
+		RecipientIDColumn                = postgres.StringColumn("recipient_id")
+		MessageIDColumn                  = postgres.StringColumn("message_id")
+		GameIDColumn                     = postgres.StringColumn("game_id")
+		UserIDColumn                     = postgres.StringColumn("user_id")
+		RecipientUserNameColumn          = postgres.StringColumn("recipient_user_name")
+		RecipientRaceNameColumn          = postgres.StringColumn("recipient_race_name")
+		RecipientPreferredLanguageColumn = postgres.StringColumn("recipient_preferred_language")
+		AvailableAtColumn                = postgres.TimestampzColumn("available_at")
+		TranslationAttemptsColumn        = postgres.IntegerColumn("translation_attempts")
+		NextTranslationAttemptAtColumn   = postgres.TimestampzColumn("next_translation_attempt_at")
+		DeliveredAtColumn                = postgres.TimestampzColumn("delivered_at")
+		ReadAtColumn                     = postgres.TimestampzColumn("read_at")
+		DeletedAtColumn                  = postgres.TimestampzColumn("deleted_at")
+		NotifiedAtColumn                 = postgres.TimestampzColumn("notified_at")
+		allColumns                       = postgres.ColumnList{RecipientIDColumn, MessageIDColumn, GameIDColumn, UserIDColumn, RecipientUserNameColumn, RecipientRaceNameColumn, RecipientPreferredLanguageColumn, AvailableAtColumn, TranslationAttemptsColumn, NextTranslationAttemptAtColumn, DeliveredAtColumn, ReadAtColumn, DeletedAtColumn, NotifiedAtColumn}
+		mutableColumns                   = postgres.ColumnList{MessageIDColumn, GameIDColumn, UserIDColumn, RecipientUserNameColumn, RecipientRaceNameColumn, RecipientPreferredLanguageColumn, AvailableAtColumn, TranslationAttemptsColumn, NextTranslationAttemptAtColumn, DeliveredAtColumn, ReadAtColumn, DeletedAtColumn, NotifiedAtColumn}
+		defaultColumns                   = postgres.ColumnList{RecipientPreferredLanguageColumn, TranslationAttemptsColumn}
+	)
+
+	return diplomailRecipientsTable{
+		Table: postgres.NewTable(schemaName, tableName, alias, allColumns...),
+
+		//Columns
+		RecipientID:                RecipientIDColumn,
+		MessageID:                  MessageIDColumn,
+		GameID:                     GameIDColumn,
+		UserID:                     UserIDColumn,
+		RecipientUserName:          RecipientUserNameColumn,
+		RecipientRaceName:          RecipientRaceNameColumn,
+		RecipientPreferredLanguage: RecipientPreferredLanguageColumn,
+		AvailableAt:                AvailableAtColumn,
+		TranslationAttempts:        TranslationAttemptsColumn,
+		NextTranslationAttemptAt:   NextTranslationAttemptAtColumn,
+		DeliveredAt:                DeliveredAtColumn,
+		ReadAt:                     ReadAtColumn,
+		DeletedAt:                  DeletedAtColumn,
+		NotifiedAt:                 NotifiedAtColumn,
+
+		AllColumns:     allColumns,
+		MutableColumns: mutableColumns,
+		DefaultColumns: defaultColumns,
+	}
+}

backend/internal/postgres/jet/backend/table/diplomail_translations.go

@@ -0,0 +1,96 @@
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
+package table
+
+import (
+	"github.com/go-jet/jet/v2/postgres"
+)
+
+var DiplomailTranslations = newDiplomailTranslationsTable("backend", "diplomail_translations", "")
+
+type diplomailTranslationsTable struct {
+	postgres.Table
+
+	// Columns
+	TranslationID     postgres.ColumnString
+	MessageID         postgres.ColumnString
+	TargetLang        postgres.ColumnString
+	TranslatedSubject postgres.ColumnString
+	TranslatedBody    postgres.ColumnString
+	Translator        postgres.ColumnString
+	TranslatedAt      postgres.ColumnTimestampz
+
+	AllColumns     postgres.ColumnList
+	MutableColumns postgres.ColumnList
+	DefaultColumns postgres.ColumnList
+}
+
+type DiplomailTranslationsTable struct {
+	diplomailTranslationsTable
+
+	EXCLUDED diplomailTranslationsTable
+}
+
+// AS creates new DiplomailTranslationsTable with assigned alias
+func (a DiplomailTranslationsTable) AS(alias string) *DiplomailTranslationsTable {
+	return newDiplomailTranslationsTable(a.SchemaName(), a.TableName(), alias)
+}
+
+// Schema creates new DiplomailTranslationsTable with assigned schema name
+func (a DiplomailTranslationsTable) FromSchema(schemaName string) *DiplomailTranslationsTable {
+	return newDiplomailTranslationsTable(schemaName, a.TableName(), a.Alias())
+}
+
+// WithPrefix creates new DiplomailTranslationsTable with assigned table prefix
+func (a DiplomailTranslationsTable) WithPrefix(prefix string) *DiplomailTranslationsTable {
+	return newDiplomailTranslationsTable(a.SchemaName(), prefix+a.TableName(), a.TableName())
+}
+
+// WithSuffix creates new DiplomailTranslationsTable with assigned table suffix
+func (a DiplomailTranslationsTable) WithSuffix(suffix string) *DiplomailTranslationsTable {
+	return newDiplomailTranslationsTable(a.SchemaName(), a.TableName()+suffix, a.TableName())
+}
+
+func newDiplomailTranslationsTable(schemaName, tableName, alias string) *DiplomailTranslationsTable {
+	return &DiplomailTranslationsTable{
+		diplomailTranslationsTable: newDiplomailTranslationsTableImpl(schemaName, tableName, alias),
+		EXCLUDED:                   newDiplomailTranslationsTableImpl("", "excluded", ""),
+	}
+}
+
+func newDiplomailTranslationsTableImpl(schemaName, tableName, alias string) diplomailTranslationsTable {
+	var (
+		TranslationIDColumn     = postgres.StringColumn("translation_id")
+		MessageIDColumn         = postgres.StringColumn("message_id")
+		TargetLangColumn        = postgres.StringColumn("target_lang")
+		TranslatedSubjectColumn = postgres.StringColumn("translated_subject")
+		TranslatedBodyColumn    = postgres.StringColumn("translated_body")
+		TranslatorColumn        = postgres.StringColumn("translator")
+		TranslatedAtColumn      = postgres.TimestampzColumn("translated_at")
+		allColumns              = postgres.ColumnList{TranslationIDColumn, MessageIDColumn, TargetLangColumn, TranslatedSubjectColumn, TranslatedBodyColumn, TranslatorColumn, TranslatedAtColumn}
+		mutableColumns          = postgres.ColumnList{MessageIDColumn, TargetLangColumn, TranslatedSubjectColumn, TranslatedBodyColumn, TranslatorColumn, TranslatedAtColumn}
+		defaultColumns          = postgres.ColumnList{TranslatedSubjectColumn, TranslatedAtColumn}
+	)
+
+	return diplomailTranslationsTable{
+		Table: postgres.NewTable(schemaName, tableName, alias, allColumns...),
+
+		//Columns
+		TranslationID:     TranslationIDColumn,
+		MessageID:         MessageIDColumn,
+		TargetLang:        TargetLangColumn,
+		TranslatedSubject: TranslatedSubjectColumn,
+		TranslatedBody:    TranslatedBodyColumn,
+		Translator:        TranslatorColumn,
+		TranslatedAt:      TranslatedAtColumn,
+
+		AllColumns:     allColumns,
+		MutableColumns: mutableColumns,
+		DefaultColumns: defaultColumns,
+	}
+}

backend/internal/postgres/jet/backend/table/table_use_schema.go

@@ -16,6 +16,9 @@ func UseSchema(schema string) {
 	AuthChallenges = AuthChallenges.FromSchema(schema)
 	BlockedEmails = BlockedEmails.FromSchema(schema)
 	DeviceSessions = DeviceSessions.FromSchema(schema)
+	DiplomailMessages = DiplomailMessages.FromSchema(schema)
+	DiplomailRecipients = DiplomailRecipients.FromSchema(schema)
+	DiplomailTranslations = DiplomailTranslations.FromSchema(schema)
 	EngineVersions = EngineVersions.FromSchema(schema)
 	EntitlementRecords = EntitlementRecords.FromSchema(schema)
 	EntitlementSnapshots = EntitlementSnapshots.FromSchema(schema)

backend/internal/postgres/migrations/00001_init.sql

@@ -418,7 +418,7 @@ CREATE INDEX race_names_pending_eligible_idx
 -- finished) and the container-state escape hatch (removed) used by
 -- reconciliation when the recorded container has disappeared.
 CREATE TABLE runtime_records (
-    game_id                  uuid        PRIMARY KEY,
+    game_id                  uuid        PRIMARY KEY REFERENCES games (game_id) ON DELETE CASCADE,
     status                   text        NOT NULL,
     current_container_id     text,
     current_image_ref        text,
@@ -465,7 +465,7 @@ CREATE TABLE engine_versions (
 -- roster reads. The partial UNIQUE on (game_id, race_name) enforces the
 -- one-race-per-game invariant at the storage boundary.
 CREATE TABLE player_mappings (
-    game_id             uuid        NOT NULL,
+    game_id             uuid        NOT NULL REFERENCES games (game_id) ON DELETE CASCADE,
     user_id             uuid        NOT NULL,
     race_name           text        NOT NULL,
     engine_player_uuid  uuid        NOT NULL,
@@ -605,7 +605,9 @@ CREATE TABLE notifications (
             'lobby.race_name.registered', 'lobby.race_name.pending',
             'lobby.race_name.expired',
             'runtime.image_pull_failed', 'runtime.container_start_failed',
-            'runtime.start_config_invalid'
+            'runtime.start_config_invalid',
+            'game.turn.ready', 'game.paused',
+            'diplomail.message.received'
         ))
 );
 
@@ -661,6 +663,114 @@ CREATE TABLE notification_malformed_intents (
 CREATE INDEX notification_malformed_intents_listing_idx
     ON notification_malformed_intents (received_at DESC);
 
+-- =====================================================================
+-- Diplomail domain
+-- =====================================================================
+
+-- diplomail_messages is the canonical record of every diplomatic-mail
+-- send: one row per personal message, owner/admin send, broadcast, or
+-- system notification. game_name is captured at insert time so the
+-- bulk-purge / rename paths still render correctly. sender_username
+-- carries either accounts.user_name (sender_kind='player') or
+-- admin_accounts.username (sender_kind='admin'); system senders leave
+-- it NULL. body and subject are plain UTF-8; length limits are enforced
+-- in the service layer and may be tuned without a migration.
+CREATE TABLE diplomail_messages (
+    message_id        uuid        PRIMARY KEY,
+    game_id           uuid        NOT NULL REFERENCES games (game_id) ON DELETE CASCADE,
+    game_name         text        NOT NULL,
+    kind              text        NOT NULL,
+    sender_kind       text        NOT NULL,
+    sender_user_id    uuid,
+    sender_username   text,
+    sender_ip         text        NOT NULL DEFAULT '',
+    subject           text        NOT NULL DEFAULT '',
+    body              text        NOT NULL,
+    body_lang         text        NOT NULL DEFAULT 'und',
+    broadcast_scope   text        NOT NULL DEFAULT 'single',
+    created_at        timestamptz NOT NULL DEFAULT now(),
+    CONSTRAINT diplomail_messages_kind_chk
+        CHECK (kind IN ('personal', 'admin')),
+    CONSTRAINT diplomail_messages_sender_kind_chk
+        CHECK (sender_kind IN ('player', 'admin', 'system')),
+    CONSTRAINT diplomail_messages_sender_identity_chk CHECK (
+        (sender_kind = 'player' AND sender_user_id IS NOT NULL AND sender_username IS NOT NULL) OR
+        (sender_kind = 'admin'  AND sender_user_id IS NULL     AND sender_username IS NOT NULL) OR
+        (sender_kind = 'system' AND sender_user_id IS NULL     AND sender_username IS NULL)
+    ),
+    CONSTRAINT diplomail_messages_kind_sender_chk CHECK (
+        (kind = 'personal' AND sender_kind = 'player') OR
+        (kind = 'admin'    AND sender_kind IN ('player', 'admin', 'system'))
+    ),
+    CONSTRAINT diplomail_messages_broadcast_scope_chk
+        CHECK (broadcast_scope IN ('single', 'game_broadcast', 'multi_game_broadcast'))
+);
+
+CREATE INDEX diplomail_messages_game_idx
+    ON diplomail_messages (game_id, created_at DESC);
+
+CREATE INDEX diplomail_messages_sender_user_idx
+    ON diplomail_messages (sender_user_id, created_at DESC)
+    WHERE sender_user_id IS NOT NULL;
+
+-- diplomail_recipients carries one row per (message, recipient). The
+-- per-user read/delete/deliver/notified state lives here. recipient
+-- snapshots (user_name, race_name) are captured at insert time so the
+-- inbox listing and admin search render without joining accounts /
+-- memberships and survive race-name renames, membership revocation,
+-- and account soft-delete. recipient_race_name is nullable for the
+-- rare admin notifications addressed to a player who no longer has an
+-- active membership in the game.
+CREATE TABLE diplomail_recipients (
+    recipient_id                  uuid        PRIMARY KEY,
+    message_id                    uuid        NOT NULL REFERENCES diplomail_messages (message_id) ON DELETE CASCADE,
+    game_id                       uuid        NOT NULL,
+    user_id                       uuid        NOT NULL,
+    recipient_user_name           text        NOT NULL,
+    recipient_race_name           text,
+    recipient_preferred_language  text        NOT NULL DEFAULT '',
+    available_at                  timestamptz,
+    translation_attempts          integer     NOT NULL DEFAULT 0,
+    next_translation_attempt_at   timestamptz,
+    delivered_at                  timestamptz,
+    read_at                       timestamptz,
+    deleted_at                    timestamptz,
+    notified_at                   timestamptz,
+    CONSTRAINT diplomail_recipients_unique UNIQUE (message_id, user_id)
+);
+
+CREATE INDEX diplomail_recipients_inbox_idx
+    ON diplomail_recipients (user_id, game_id, deleted_at, read_at);
+
+CREATE INDEX diplomail_recipients_unread_idx
+    ON diplomail_recipients (user_id, game_id)
+    WHERE read_at IS NULL AND deleted_at IS NULL AND available_at IS NOT NULL;
+
+-- Index drives the translation worker's pending-pair pickup. The
+-- partial filter keeps the scan tight: terminal-state recipients
+-- (with a non-NULL available_at) never appear in this btree. The
+-- composite ordering puts the next-attempt clock first so the
+-- backoff filter (`next_translation_attempt_at <= now()`) seeks
+-- before the secondary cluster on (message_id, lang).
+CREATE INDEX diplomail_recipients_pending_translation_idx
+    ON diplomail_recipients (next_translation_attempt_at, message_id, recipient_preferred_language)
+    WHERE available_at IS NULL;
+
+-- diplomail_translations caches one rendered translation per
+-- (message, target_lang) so a broadcast addressed to many recipients
+-- with the same preferred_language is translated once. translator
+-- identifies the backend that produced the row.
+CREATE TABLE diplomail_translations (
+    translation_id      uuid        PRIMARY KEY,
+    message_id          uuid        NOT NULL REFERENCES diplomail_messages (message_id) ON DELETE CASCADE,
+    target_lang         text        NOT NULL,
+    translated_subject  text        NOT NULL DEFAULT '',
+    translated_body     text        NOT NULL,
+    translator          text        NOT NULL,
+    translated_at       timestamptz NOT NULL DEFAULT now(),
+    CONSTRAINT diplomail_translations_unique UNIQUE (message_id, target_lang)
+);
+
 -- =====================================================================
 -- Geo domain
 -- =====================================================================

backend/internal/postgres/migrations_test.go

@@ -68,6 +68,10 @@ var expectedBackendTables = []string{
 	"notification_malformed_intents",
 	"notification_routes",
 	"notifications",
+	// Diplomail domain.
+	"diplomail_messages",
+	"diplomail_recipients",
+	"diplomail_translations",
 	// Geo domain.
 	"user_country_counters",
 }

backend/internal/runtime/errors.go

@@ -42,4 +42,23 @@ var (
 	// ErrShutdown means the runtime service has stopped accepting
 	// work because the parent context was cancelled.
 	ErrShutdown = errors.New("runtime: shutting down")
+
+	// ErrTurnAlreadyClosed reports that the runtime is currently
+	// producing a turn — runtime status is `generation_in_progress`
+	// — and the engine is not accepting writes for the closing
+	// turn. Handlers map this to HTTP 409 with httperr code
+	// `turn_already_closed`; the UI shows a conflict banner and
+	// waits for the next `game.turn.ready` push.
+	ErrTurnAlreadyClosed = errors.New("runtime: turn already closed")
+
+	// ErrGamePaused reports that the game is not in a state that
+	// accepts user-games commands or orders: the runtime row
+	// carries `paused = true`, or the runtime status lands on any
+	// terminal value (`engine_unreachable`, `generation_failed`,
+	// `stopped`, `finished`, `removed`), or the game has not yet
+	// finished bootstrapping (`starting`). Handlers map this to
+	// HTTP 409 with httperr code `game_paused`; the UI surfaces a
+	// pause banner and waits for an admin resume or a fresh
+	// snapshot.
+	ErrGamePaused = errors.New("runtime: game paused")
 )

backend/internal/runtime/orders_accept_test.go

@@ -0,0 +1,82 @@
+package runtime
+
+import (
+	"errors"
+	"testing"
+)
+
+// TestOrdersAcceptStatus pins down the Phase 25 pre-check that
+// gates the user-games command/order handlers against the runtime
+// record. The decision must distinguish a turn cutoff (engine is
+// producing) from a paused game so the UI can surface the right
+// banner; all other non-running runtime statuses collapse into
+// `ErrGamePaused`.
+func TestOrdersAcceptStatus(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		rec  RuntimeRecord
+		want error
+	}{
+		{
+			name: "running and not paused accepts orders",
+			rec:  RuntimeRecord{Status: RuntimeStatusRunning, Paused: false},
+			want: nil,
+		},
+		{
+			name: "running but paused returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusRunning, Paused: true},
+			want: ErrGamePaused,
+		},
+		{
+			name: "generation in progress returns turn already closed",
+			rec:  RuntimeRecord{Status: RuntimeStatusGenerationInProgress},
+			want: ErrTurnAlreadyClosed,
+		},
+		{
+			name: "generation failed returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusGenerationFailed},
+			want: ErrGamePaused,
+		},
+		{
+			name: "engine unreachable returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusEngineUnreachable},
+			want: ErrGamePaused,
+		},
+		{
+			name: "stopped returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusStopped},
+			want: ErrGamePaused,
+		},
+		{
+			name: "finished returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusFinished},
+			want: ErrGamePaused,
+		},
+		{
+			name: "removed returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusRemoved},
+			want: ErrGamePaused,
+		},
+		{
+			name: "starting returns game paused",
+			rec:  RuntimeRecord{Status: RuntimeStatusStarting},
+			want: ErrGamePaused,
+		},
+		{
+			name: "paused takes precedence over generation in progress",
+			rec:  RuntimeRecord{Status: RuntimeStatusGenerationInProgress, Paused: true},
+			want: ErrGamePaused,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got := OrdersAcceptStatus(tt.rec)
+			if !errors.Is(got, tt.want) {
+				t.Errorf("OrdersAcceptStatus = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

backend/internal/runtime/scheduler.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"galaxy/backend/internal/dockerclient"
+	"galaxy/backend/internal/engineclient"
 	"galaxy/cronutil"
 
 	"github.com/google/uuid"
@@ -213,6 +214,22 @@ func (sch *Scheduler) loop(ctx context.Context, rec RuntimeRecord, done chan str
 
 // tick runs one engine /admin/turn call under the per-game mutex,
 // publishes the resulting snapshot, and clears `skip_next_tick`.
+//
+// Phase 25 wraps the engine call between two runtime-status flips so
+// the backend order handler can reject late submits while the engine
+// is producing:
+//
+//   - before `Engine.Turn`: runtime status moves to
+//     `generation_in_progress`; the loop's running-only guard tolerates
+//     this because the flip back happens inside the same tick.
+//   - on success: runtime status moves back to `running` (unless the
+//     engine reports `finished`, in which case `publishSnapshot` has
+//     already promoted the row to `finished`).
+//   - on error: runtime status moves to `generation_failed` (engine
+//     validation failure) or `engine_unreachable` (transport / 5xx).
+//     The matching snapshot is forwarded to lobby through
+//     `publishFailureSnapshot` so lobby can flip the game to `paused`
+//     and emit `game.paused`.
 func (sch *Scheduler) tick(ctx context.Context, rec RuntimeRecord) error {
 	mu := sch.svc.gameLock(rec.GameID)
 	if !mu.TryLock() {
@@ -224,10 +241,24 @@ func (sch *Scheduler) tick(ctx context.Context, rec RuntimeRecord) error {
 	if err != nil {
 		return err
 	}
+	if _, err := sch.svc.transitionRuntimeStatus(ctx, rec.GameID, RuntimeStatusGenerationInProgress, ""); err != nil {
+		sch.svc.completeOperation(ctx, op, err)
+		return err
+	}
 	state, err := sch.svc.deps.Engine.Turn(ctx, rec.EngineEndpoint)
 	if err != nil {
 		sch.svc.completeOperation(ctx, op, err)
-		_, _ = sch.svc.transitionRuntimeStatus(ctx, rec.GameID, RuntimeStatusEngineUnreachable, "")
+		failureStatus := RuntimeStatusEngineUnreachable
+		if errors.Is(err, engineclient.ErrEngineValidation) {
+			failureStatus = RuntimeStatusGenerationFailed
+		}
+		_, _ = sch.svc.transitionRuntimeStatus(ctx, rec.GameID, failureStatus, "down")
+		if pubErr := sch.svc.publishFailureSnapshot(ctx, rec.GameID, failureStatus); pubErr != nil {
+			sch.svc.deps.Logger.Warn("publish failure snapshot to lobby",
+				zap.String("game_id", rec.GameID.String()),
+				zap.String("runtime_status", failureStatus),
+				zap.Error(pubErr))
+		}
 		// On engine unreachable, also clear skip_next_tick so the next
 		// real tick can start fresh.
 		_ = sch.clearSkipFlag(ctx, rec.GameID)
@@ -244,6 +275,12 @@ func (sch *Scheduler) tick(ctx context.Context, rec RuntimeRecord) error {
 		sch.svc.completeOperation(ctx, op, err)
 		return err
 	}
+	if !state.Finished {
+		// `publishSnapshot` patches CurrentTurn / EngineHealth but does
+		// not reset the status column; reopen the orders window here so
+		// the next loop iteration finds the runtime back in `running`.
+		_, _ = sch.svc.transitionRuntimeStatus(ctx, rec.GameID, RuntimeStatusRunning, "ok")
+	}
 	sch.svc.completeOperation(ctx, op, nil)
 	_ = sch.clearSkipFlag(ctx, rec.GameID)
 	return nil

backend/internal/runtime/service.go

@@ -257,6 +257,57 @@ func (s *Service) ResolvePlayerMapping(ctx context.Context, gameID, userID uuid.
 	return s.deps.Store.LoadPlayerMapping(ctx, gameID, userID)
 }
 
+// CheckOrdersAccept verifies that the runtime is in a state that
+// accepts user-games commands and orders. It is called by the user
+// game-proxy handlers (`Commands`, `Orders`) before forwarding to
+// engine, so the backend's turn-cutoff and pause guards run before
+// network traffic leaves the host. The decision itself lives in the
+// pure helper `OrdersAcceptStatus` so it can be unit-tested without
+// constructing a full Service.
+//
+// A missing runtime row is surfaced as `ErrNotFound` so the handler
+// keeps its existing 404 behaviour.
+func (s *Service) CheckOrdersAccept(ctx context.Context, gameID uuid.UUID) error {
+	rec, err := s.GetRuntime(ctx, gameID)
+	if err != nil {
+		return err
+	}
+	return OrdersAcceptStatus(rec)
+}
+
+// OrdersAcceptStatus inspects a runtime record and returns the
+// matching sentinel for the user-games order/command pre-check:
+//
+//   - `runtime_status = generation_in_progress` → `ErrTurnAlreadyClosed`.
+//     The cron-driven `Scheduler.tick` has flipped the row before
+//     calling the engine. The order window reopens once the tick
+//     completes successfully.
+//
+//   - `runtime_status ∈ {engine_unreachable, generation_failed,
+//     stopped, finished, removed, starting}` → `ErrGamePaused`.
+//     The game is not in a state that accepts writes; the lobby
+//     state machine has either already flipped the game to
+//     `paused` / `finished` or is still bootstrapping.
+//
+//   - `runtime.Paused = true` → `ErrGamePaused`. The lobby admin
+//     paused the game explicitly.
+//
+//   - `runtime_status = running` and `Paused = false` → nil
+//     (forward).
+func OrdersAcceptStatus(rec RuntimeRecord) error {
+	if rec.Paused {
+		return ErrGamePaused
+	}
+	switch rec.Status {
+	case RuntimeStatusRunning:
+		return nil
+	case RuntimeStatusGenerationInProgress:
+		return ErrTurnAlreadyClosed
+	default:
+		return ErrGamePaused
+	}
+}
+
 // EngineEndpoint returns the engine endpoint URL for gameID. Used by
 // the user game-proxy handlers.
 func (s *Service) EngineEndpoint(ctx context.Context, gameID uuid.UUID) (string, error) {
@@ -812,6 +863,33 @@ func (s *Service) publishSnapshot(ctx context.Context, gameID uuid.UUID, state r
 	return nil
 }
 
+// publishFailureSnapshot forwards a runtime-failure observation to
+// lobby so the game lifecycle can react (e.g. flipping `running` to
+// `paused` on `engine_unreachable` / `generation_failed` per Phase
+// 25). The snapshot carries the unchanged `current_turn` because no
+// new turn has been produced; lobby uses the turn number to anchor
+// the `game.paused` idempotency key.
+//
+// The call is best-effort: lobby errors are returned to the caller
+// (the scheduler tick) so the warn-level logging stays in one place.
+// A missing runtime cache entry (e.g. the row was just removed by
+// the reconciler) collapses into a silent no-op.
+func (s *Service) publishFailureSnapshot(ctx context.Context, gameID uuid.UUID, runtimeStatus string) error {
+	if s.deps.Lobby == nil {
+		return nil
+	}
+	rec, ok := s.deps.Cache.GetRuntime(gameID)
+	if !ok {
+		return nil
+	}
+	return s.deps.Lobby.OnRuntimeSnapshot(ctx, gameID, LobbySnapshot{
+		CurrentTurn:   rec.CurrentTurn,
+		RuntimeStatus: runtimeStatus,
+		EngineHealth:  "down",
+		ObservedAt:    s.deps.Now().UTC(),
+	})
+}
+
 // transitionRuntimeStatus updates the status / engine_health columns
 // and refreshes the cache.
 func (s *Service) transitionRuntimeStatus(ctx context.Context, gameID uuid.UUID, status, health string) (RuntimeRecord, error) {

backend/internal/runtime/service_e2e_test.go

@@ -200,6 +200,8 @@ func TestServiceStartGameEndToEnd(t *testing.T) {
 	engineSrv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		switch r.URL.Path {
+		case "/healthz":
+			w.WriteHeader(http.StatusOK)
 		case "/api/v1/admin/init":
 			_ = json.NewEncoder(w).Encode(rest.StateResponse{ID: gameID, Turn: 0, Players: []rest.PlayerState{{RaceName: "Alpha", Planets: 3, Population: 10}}})
 		case "/api/v1/admin/status":

backend/internal/server/contract_test.go

@@ -45,11 +45,21 @@ var pathParamStubs = map[string]string{
 	"delivery_id": "00000000-0000-0000-0000-000000000006",
 	"user_id": "00000000-0000-0000-0000-000000000007",
 	"device_session_id": "00000000-0000-0000-0000-000000000008",
+	"battle_id": "00000000-0000-0000-0000-000000000009",
+	"message_id": "00000000-0000-0000-0000-00000000000a",
 	"id": "1.2.3",
 	"username": "alice",
 	"turn": "42",
 }
 
+// queryParamStubs lists the deterministic substitutions used to fill
+// query-string parameters declared in `openapi.yaml`. Every required
+// query parameter must have an entry here; optional ones can stay
+// blank (the contract test omits them when no stub is registered).
+var queryParamStubs = map[string]string{
+	"turn": "42",
+}
+
 // requestBodyStubs lists the JSON request bodies the contract test sends for
 // each operationId. Operations missing from the map default to an empty
 // object `{}`, which is a valid placeholder thanks to `additionalProperties:
@@ -140,6 +150,35 @@ var requestBodyStubs = map[string]map[string]any{
 		"user_id": pathParamStubs["user_id"],
 		"reason": "ToS violation",
 	},
+	"userMailSendPersonal": {
+		"recipient_user_id": pathParamStubs["user_id"],
+		"subject": "Contract test subject",
+		"body": "Contract test body",
+	},
+	"userMailSendAdmin": {
+		"target": "user",
+		"recipient_user_id": pathParamStubs["user_id"],
+		"subject": "Contract test admin subject",
+		"body": "Contract test admin body",
+	},
+	"adminDiplomailSend": {
+		"target": "user",
+		"recipient_user_id": pathParamStubs["user_id"],
+		"subject": "Contract test admin subject",
+		"body": "Contract test admin body",
+	},
+	"userMailSendBroadcast": {
+		"subject": "Contract test paid broadcast",
+		"body": "Contract test paid broadcast body",
+	},
+	"adminDiplomailBroadcast": {
+		"scope": "all_running",
+		"subject": "Contract test multi-game broadcast",
+		"body": "Contract test multi-game broadcast body",
+	},
+	"adminDiplomailCleanup": {
+		"older_than_years": 1,
+	},
 }
 
 // TestOpenAPIContract is the top-level OpenAPI contract test. It
@@ -323,6 +362,9 @@ func buildRequest(t *testing.T, c contractOperation) *http.Request {
 	t.Helper()
 
 	target := substitutePathParams(t, c.path)
+	if query := buildQuery(t, c); query != "" {
+		target += "?" + query
+	}
 	url := "http://backend.internal" + target
 
 	body := bodyFor(t, c)
@@ -376,6 +418,31 @@ func bodyFor(t *testing.T, c contractOperation) requestBody {
 	}
 }
 
+func buildQuery(t *testing.T, c contractOperation) string {
+	t.Helper()
+	if c.op == nil {
+		return ""
+	}
+	values := make([]string, 0, len(c.op.Parameters))
+	for _, p := range c.op.Parameters {
+		if p == nil || p.Value == nil {
+			continue
+		}
+		if p.Value.In != "query" {
+			continue
+		}
+		stub, ok := queryParamStubs[p.Value.Name]
+		if !ok {
+			if p.Value.Required {
+				t.Fatalf("operation %q requires query parameter %q with no stub registered", c.operationID, p.Value.Name)
+			}
+			continue
+		}
+		values = append(values, p.Value.Name+"="+stub)
+	}
+	return strings.Join(values, "&")
+}
+
 func substitutePathParams(t *testing.T, templated string) string {
 	t.Helper()
 

backend/internal/server/handlers_admin_diplomail.go

@@ -0,0 +1,326 @@
+package server
+
+import (
+	"net/http"
+
+	"galaxy/backend/internal/diplomail"
+	"galaxy/backend/internal/server/clientip"
+	"galaxy/backend/internal/server/handlers"
+	"galaxy/backend/internal/server/httperr"
+	"galaxy/backend/internal/server/middleware/basicauth"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// AdminDiplomailHandlers groups the diplomatic-mail handlers exposed
+// under `/api/v1/admin/games/{game_id}/mail` (per-game admin send /
+// broadcast). The handler is intentionally separate from
+// `AdminMailHandlers`, which owns the unrelated email outbox surface
+// under `/api/v1/admin/mail/*`.
+type AdminDiplomailHandlers struct {
+	svc    *diplomail.Service
+	logger *zap.Logger
+}
+
+// NewAdminDiplomailHandlers constructs the handler set. svc may be
+// nil — in that case every handler returns 501 not_implemented.
+func NewAdminDiplomailHandlers(svc *diplomail.Service, logger *zap.Logger) *AdminDiplomailHandlers {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	return &AdminDiplomailHandlers{svc: svc, logger: logger.Named("http.admin.diplomail")}
+}
+
+// Send handles POST /api/v1/admin/games/{game_id}/mail. The body
+// shape mirrors the owner route: `target="user"` requires
+// `recipient_user_id`; `target="all"` accepts an optional
+// `recipients` scope. The authenticated admin username is captured
+// from the basicauth context and persisted as `sender_username`.
+func (h *AdminDiplomailHandlers) Send() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("adminDiplomailSend")
+	}
+	return func(c *gin.Context) {
+		username, ok := basicauth.UsernameFromContext(c.Request.Context())
+		if !ok || username == "" {
+			httperr.Abort(c, http.StatusUnauthorized, httperr.CodeUnauthorized, "admin authentication is required")
+			return
+		}
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		var req userMailSendAdminRequestWire
+		if err := c.ShouldBindJSON(&req); err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be valid JSON")
+			return
+		}
+		ctx := c.Request.Context()
+		switch req.Target {
+		case "", "user":
+			recipientID, parseErr := uuid.Parse(req.RecipientUserID)
+			if parseErr != nil {
+				httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "recipient_user_id must be a valid UUID")
+				return
+			}
+			msg, rcpt, sendErr := h.svc.SendAdminPersonal(ctx, diplomail.SendAdminPersonalInput{
+				GameID:          gameID,
+				CallerKind:      diplomail.CallerKindAdmin,
+				CallerUsername:  username,
+				RecipientUserID: recipientID,
+				Subject:         req.Subject,
+				Body:            req.Body,
+				SenderIP:        clientip.ExtractSourceIP(c),
+			})
+			if sendErr != nil {
+				respondDiplomailError(c, h.logger, "admin mail send personal", ctx, sendErr)
+				return
+			}
+			c.JSON(http.StatusCreated, mailMessageDetailToWire(diplomail.InboxEntry{Message: msg, Recipient: rcpt}, true))
+		case "all":
+			msg, recipients, sendErr := h.svc.SendAdminBroadcast(ctx, diplomail.SendAdminBroadcastInput{
+				GameID:         gameID,
+				CallerKind:     diplomail.CallerKindAdmin,
+				CallerUsername: username,
+				RecipientScope: req.Recipients,
+				Subject:        req.Subject,
+				Body:           req.Body,
+				SenderIP:       clientip.ExtractSourceIP(c),
+			})
+			if sendErr != nil {
+				respondDiplomailError(c, h.logger, "admin mail send broadcast", ctx, sendErr)
+				return
+			}
+			c.JSON(http.StatusCreated, mailBroadcastReceiptToWire(msg, recipients))
+		default:
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "target must be 'user' or 'all'")
+		}
+	}
+}
+
+// Broadcast handles POST /api/v1/admin/mail/broadcast. Body:
+//
+//	{
+//	  "scope": "selected" | "all_running",
+//	  "game_ids": ["..."],
+//	  "recipients": "active" | "active_and_removed" | "all_members",
+//	  "subject": "...",
+//	  "body": "..."
+//	}
+//
+// The handler routes through SendAdminMultiGameBroadcast and returns
+// a fan-out receipt describing the message ids created and the
+// total recipient count.
+func (h *AdminDiplomailHandlers) Broadcast() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("adminDiplomailBroadcast")
+	}
+	return func(c *gin.Context) {
+		username, ok := basicauth.UsernameFromContext(c.Request.Context())
+		if !ok || username == "" {
+			httperr.Abort(c, http.StatusUnauthorized, httperr.CodeUnauthorized, "admin authentication is required")
+			return
+		}
+		var req adminDiplomailBroadcastRequestWire
+		if err := c.ShouldBindJSON(&req); err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be valid JSON")
+			return
+		}
+		gameIDs := make([]uuid.UUID, 0, len(req.GameIDs))
+		for _, raw := range req.GameIDs {
+			parsed, err := uuid.Parse(raw)
+			if err != nil {
+				httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "game_ids must be valid UUIDs")
+				return
+			}
+			gameIDs = append(gameIDs, parsed)
+		}
+		ctx := c.Request.Context()
+		msgs, total, err := h.svc.SendAdminMultiGameBroadcast(ctx, diplomail.SendMultiGameBroadcastInput{
+			CallerUsername: username,
+			Scope:          req.Scope,
+			GameIDs:        gameIDs,
+			RecipientScope: req.Recipients,
+			Subject:        req.Subject,
+			Body:           req.Body,
+			SenderIP:       clientip.ExtractSourceIP(c),
+		})
+		if err != nil {
+			respondDiplomailError(c, h.logger, "admin mail broadcast", ctx, err)
+			return
+		}
+		out := adminDiplomailBroadcastResponseWire{
+			RecipientCount: total,
+			Messages:       make([]adminDiplomailBroadcastMessageWire, 0, len(msgs)),
+		}
+		for _, m := range msgs {
+			out.Messages = append(out.Messages, adminDiplomailBroadcastMessageWire{
+				MessageID: m.MessageID.String(),
+				GameID:    m.GameID.String(),
+				GameName:  m.GameName,
+			})
+		}
+		c.JSON(http.StatusCreated, out)
+	}
+}
+
+// Cleanup handles POST /api/v1/admin/mail/cleanup. Body:
+//
+//	{ "older_than_years": 1 }
+//
+// The endpoint removes every diplomail_messages row whose game
+// finished more than the supplied number of years ago. The cascade
+// on the recipient and translation tables prunes the per-user state
+// in the same transaction. Returns a CleanupResult envelope.
+func (h *AdminDiplomailHandlers) Cleanup() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("adminDiplomailCleanup")
+	}
+	return func(c *gin.Context) {
+		username, ok := basicauth.UsernameFromContext(c.Request.Context())
+		if !ok || username == "" {
+			httperr.Abort(c, http.StatusUnauthorized, httperr.CodeUnauthorized, "admin authentication is required")
+			return
+		}
+		_ = username
+		var req adminDiplomailCleanupRequestWire
+		if err := c.ShouldBindJSON(&req); err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be valid JSON")
+			return
+		}
+		ctx := c.Request.Context()
+		result, err := h.svc.BulkCleanup(ctx, diplomail.BulkCleanupInput{OlderThanYears: req.OlderThanYears})
+		if err != nil {
+			respondDiplomailError(c, h.logger, "admin mail cleanup", ctx, err)
+			return
+		}
+		out := adminDiplomailCleanupResponseWire{
+			MessagesDeleted: result.MessagesDeleted,
+			GameIDs:         make([]string, 0, len(result.GameIDs)),
+		}
+		for _, id := range result.GameIDs {
+			out.GameIDs = append(out.GameIDs, id.String())
+		}
+		c.JSON(http.StatusOK, out)
+	}
+}
+
+// List handles GET /api/v1/admin/mail/messages. Supports pagination
+// via `page` and `page_size`, plus optional `game_id`, `kind`, and
+// `sender_kind` filters.
+func (h *AdminDiplomailHandlers) List() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("adminDiplomailList")
+	}
+	return func(c *gin.Context) {
+		username, ok := basicauth.UsernameFromContext(c.Request.Context())
+		if !ok || username == "" {
+			httperr.Abort(c, http.StatusUnauthorized, httperr.CodeUnauthorized, "admin authentication is required")
+			return
+		}
+		filter := diplomail.AdminMessageListing{
+			Page:       parsePositiveQueryInt(c.Query("page"), 1),
+			PageSize:   parsePositiveQueryInt(c.Query("page_size"), 50),
+			Kind:       c.Query("kind"),
+			SenderKind: c.Query("sender_kind"),
+		}
+		if raw := c.Query("game_id"); raw != "" {
+			parsed, err := uuid.Parse(raw)
+			if err != nil {
+				httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "game_id must be a valid UUID")
+				return
+			}
+			filter.GameID = &parsed
+		}
+		ctx := c.Request.Context()
+		page, err := h.svc.ListMessagesForAdmin(ctx, filter)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "admin mail list", ctx, err)
+			return
+		}
+		out := adminDiplomailListResponseWire{
+			Total:    page.Total,
+			Page:     page.Page,
+			PageSize: page.PageSize,
+			Items:    make([]adminDiplomailMessageWire, 0, len(page.Items)),
+		}
+		for _, m := range page.Items {
+			entry := adminDiplomailMessageWire{
+				MessageID:      m.MessageID.String(),
+				GameID:         m.GameID.String(),
+				GameName:       m.GameName,
+				Kind:           m.Kind,
+				SenderKind:     m.SenderKind,
+				SenderIP:       m.SenderIP,
+				Subject:        m.Subject,
+				Body:           m.Body,
+				BodyLang:       m.BodyLang,
+				BroadcastScope: m.BroadcastScope,
+				CreatedAt:      m.CreatedAt.UTC().Format(timestampLayout),
+			}
+			if m.SenderUserID != nil {
+				s := m.SenderUserID.String()
+				entry.SenderUserID = &s
+			}
+			if m.SenderUsername != nil {
+				s := *m.SenderUsername
+				entry.SenderUsername = &s
+			}
+			out.Items = append(out.Items, entry)
+		}
+		c.JSON(http.StatusOK, out)
+	}
+}
+
+type adminDiplomailBroadcastRequestWire struct {
+	Scope      string   `json:"scope"`
+	GameIDs    []string `json:"game_ids,omitempty"`
+	Recipients string   `json:"recipients,omitempty"`
+	Subject    string   `json:"subject,omitempty"`
+	Body       string   `json:"body"`
+}
+
+type adminDiplomailBroadcastMessageWire struct {
+	MessageID string `json:"message_id"`
+	GameID    string `json:"game_id"`
+	GameName  string `json:"game_name,omitempty"`
+}
+
+type adminDiplomailBroadcastResponseWire struct {
+	RecipientCount int                                  `json:"recipient_count"`
+	Messages       []adminDiplomailBroadcastMessageWire `json:"messages"`
+}
+
+type adminDiplomailCleanupRequestWire struct {
+	OlderThanYears int `json:"older_than_years"`
+}
+
+type adminDiplomailCleanupResponseWire struct {
+	MessagesDeleted int      `json:"messages_deleted"`
+	GameIDs         []string `json:"game_ids"`
+}
+
+type adminDiplomailMessageWire struct {
+	MessageID      string  `json:"message_id"`
+	GameID         string  `json:"game_id"`
+	GameName       string  `json:"game_name,omitempty"`
+	Kind           string  `json:"kind"`
+	SenderKind     string  `json:"sender_kind"`
+	SenderUserID   *string `json:"sender_user_id,omitempty"`
+	SenderUsername *string `json:"sender_username,omitempty"`
+	SenderIP       string  `json:"sender_ip,omitempty"`
+	Subject        string  `json:"subject,omitempty"`
+	Body           string  `json:"body"`
+	BodyLang       string  `json:"body_lang"`
+	BroadcastScope string  `json:"broadcast_scope"`
+	CreatedAt      string  `json:"created_at"`
+}
+
+type adminDiplomailListResponseWire struct {
+	Total    int                          `json:"total"`
+	Page     int                          `json:"page"`
+	PageSize int                          `json:"page_size"`
+	Items    []adminDiplomailMessageWire  `json:"items"`
+}

backend/internal/server/handlers_user_games.go

@@ -14,7 +14,6 @@ import (
 	"galaxy/backend/internal/server/httperr"
 	"galaxy/backend/internal/server/middleware/userid"
 	"galaxy/backend/internal/telemetry"
-	"galaxy/model/order"
 	gamerest "galaxy/model/rest"
 
 	"github.com/gin-gonic/gin"
@@ -26,8 +25,8 @@ import (
 // `engineclient` against running engine containers.
 type UserGamesHandlers struct {
 	runtime *runtime.Service
-	engine *engineclient.Client
+	engine  *engineclient.Client
-	logger *zap.Logger
+	logger  *zap.Logger
 }
 
 // NewUserGamesHandlers constructs the handler set. When runtime or
@@ -61,6 +60,10 @@ func (h *UserGamesHandlers) Commands() gin.HandlerFunc {
 			return
 		}
 		ctx := c.Request.Context()
+		if err := h.runtime.CheckOrdersAccept(ctx, gameID); err != nil {
+			respondGameProxyError(c, h.logger, "user games commands", ctx, err)
+			return
+		}
 		mapping, err := h.runtime.ResolvePlayerMapping(ctx, gameID, userID)
 		if err != nil {
 			respondGameProxyError(c, h.logger, "user games commands", ctx, err)
@@ -106,6 +109,10 @@ func (h *UserGamesHandlers) Orders() gin.HandlerFunc {
 			return
 		}
 		ctx := c.Request.Context()
+		if err := h.runtime.CheckOrdersAccept(ctx, gameID); err != nil {
+			respondGameProxyError(c, h.logger, "user games orders", ctx, err)
+			return
+		}
 		mapping, err := h.runtime.ResolvePlayerMapping(ctx, gameID, userID)
 		if err != nil {
 			respondGameProxyError(c, h.logger, "user games orders", ctx, err)
@@ -123,7 +130,6 @@ func (h *UserGamesHandlers) Orders() gin.HandlerFunc {
 		// handler. Per ARCHITECTURE.md §9 backend is the only caller
 		// of the engine, so the body never carries a client-supplied
 		// actor.
-		_ = order.Order{}
 		payload, err := rebindActor(body, mapping.RaceName)
 		if err != nil {
 			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be a JSON object")
@@ -138,6 +144,64 @@ func (h *UserGamesHandlers) Orders() gin.HandlerFunc {
 	}
 }
 
+// GetOrders handles GET /api/v1/user/games/{game_id}/orders?turn=N.
+// Forwards to the engine's `GET /api/v1/order` with the player rebound
+// from the runtime mapping. The query parameter `turn` is required
+// and must be a non-negative integer; the engine itself enforces the
+// same rule, but rejecting up-front saves a network hop.
+//
+// On `204 No Content` the handler answers `204` so the gateway can
+// translate the FBS envelope to `found = false`. On `200` the
+// engine's body is forwarded verbatim — the gateway re-encodes the
+// JSON `UserGamesOrder` shape into FlatBuffers.
+func (h *UserGamesHandlers) GetOrders() gin.HandlerFunc {
+	if h == nil || h.runtime == nil || h.engine == nil {
+		return handlers.NotImplemented("userGamesGetOrders")
+	}
+	return func(c *gin.Context) {
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		turnRaw := c.Query("turn")
+		if turnRaw == "" {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "turn is required")
+			return
+		}
+		turn, err := strconv.Atoi(turnRaw)
+		if err != nil || turn < 0 {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "turn must be a non-negative integer")
+			return
+		}
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "user id missing")
+			return
+		}
+		ctx := c.Request.Context()
+		mapping, err := h.runtime.ResolvePlayerMapping(ctx, gameID, userID)
+		if err != nil {
+			respondGameProxyError(c, h.logger, "user games get orders", ctx, err)
+			return
+		}
+		endpoint, err := h.runtime.EngineEndpoint(ctx, gameID)
+		if err != nil {
+			respondGameProxyError(c, h.logger, "user games get orders", ctx, err)
+			return
+		}
+		body, status, err := h.engine.GetOrder(ctx, endpoint, mapping.RaceName, turn)
+		if err != nil {
+			respondEngineProxyError(c, h.logger, "user games get orders", ctx, body, err)
+			return
+		}
+		if status == http.StatusNoContent {
+			c.Status(http.StatusNoContent)
+			return
+		}
+		c.Data(http.StatusOK, "application/json", body)
+	}
+}
+
 // Report handles GET /api/v1/user/games/{game_id}/reports/{turn}.
 func (h *UserGamesHandlers) Report() gin.HandlerFunc {
 	if h == nil || h.runtime == nil || h.engine == nil {
@@ -179,6 +243,60 @@ func (h *UserGamesHandlers) Report() gin.HandlerFunc {
 	}
 }
 
+// Battle handles GET /api/v1/user/games/{game_id}/battles/{turn}/{battle_id}.
+// Forwards to the engine's `GET /api/v1/battle/:turn/:uuid`. Path
+// parameters are validated up-front to save a network hop. 404 from
+// the engine is forwarded as 404. The recipient race is resolved
+// from the runtime mapping but not forwarded — engine returns the
+// battle by id, visibility is enforced by the engine state.
+func (h *UserGamesHandlers) Battle() gin.HandlerFunc {
+	if h == nil || h.runtime == nil || h.engine == nil {
+		return handlers.NotImplemented("userGamesBattle")
+	}
+	return func(c *gin.Context) {
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		turnRaw := c.Param("turn")
+		turn, err := strconv.Atoi(turnRaw)
+		if err != nil || turn < 0 {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "turn must be a non-negative integer")
+			return
+		}
+		battleID := c.Param("battle_id")
+		if battleID == "" {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "battle id is required")
+			return
+		}
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "user id missing")
+			return
+		}
+		ctx := c.Request.Context()
+		if _, err := h.runtime.ResolvePlayerMapping(ctx, gameID, userID); err != nil {
+			respondGameProxyError(c, h.logger, "user games battle", ctx, err)
+			return
+		}
+		endpoint, err := h.runtime.EngineEndpoint(ctx, gameID)
+		if err != nil {
+			respondGameProxyError(c, h.logger, "user games battle", ctx, err)
+			return
+		}
+		body, status, err := h.engine.FetchBattle(ctx, endpoint, turn, battleID)
+		if err != nil {
+			respondEngineProxyError(c, h.logger, "user games battle", ctx, body, err)
+			return
+		}
+		if status == http.StatusNotFound {
+			httperr.Abort(c, http.StatusNotFound, httperr.CodeNotFound, "battle not found")
+			return
+		}
+		c.Data(http.StatusOK, "application/json", body)
+	}
+}
+
 // rebindActor decodes a JSON object from raw, sets `actor` to
 // raceName, and re-encodes. Backend never trusts the actor field
 // supplied by the client (per ARCHITECTURE.md §9).
@@ -201,6 +319,12 @@ func respondGameProxyError(c *gin.Context, logger *zap.Logger, op string, ctx co
 	switch {
 	case errors.Is(err, runtime.ErrNotFound):
 		httperr.Abort(c, http.StatusNotFound, httperr.CodeNotFound, "no runtime mapping for this user/game")
+	case errors.Is(err, runtime.ErrTurnAlreadyClosed):
+		httperr.Abort(c, http.StatusConflict, httperr.CodeTurnAlreadyClosed,
+			"turn already closed; orders are not accepted while the engine is producing")
+	case errors.Is(err, runtime.ErrGamePaused):
+		httperr.Abort(c, http.StatusConflict, httperr.CodeGamePaused,
+			"game is paused; orders are not accepted until it resumes")
 	case errors.Is(err, runtime.ErrConflict):
 		httperr.Abort(c, http.StatusConflict, httperr.CodeConflict, err.Error())
 	default:

backend/internal/server/handlers_user_lobby_helpers.go

@@ -89,9 +89,12 @@ type gameSummaryWire struct {
 	EnrollmentEndsAt string  `json:"enrollment_ends_at"`
 	CreatedAt        string  `json:"created_at"`
 	UpdatedAt        string  `json:"updated_at"`
+	CurrentTurn      int32   `json:"current_turn"`
 }
 
 // lobbyGameDetailWire mirrors `LobbyGameDetail` from openapi.yaml.
+// `current_turn` is inherited from `gameSummaryWire`; the runtime
+// fields below carry the runtime projection on top of it.
 type lobbyGameDetailWire struct {
 	gameSummaryWire
 	Visibility          string  `json:"visibility"`
@@ -100,7 +103,6 @@ type lobbyGameDetailWire struct {
 	TargetEngineVersion string  `json:"target_engine_version"`
 	StartGapHours       int32   `json:"start_gap_hours"`
 	StartGapPlayers     int32   `json:"start_gap_players"`
-	CurrentTurn         int32   `json:"current_turn"`
 	RuntimeStatus       string  `json:"runtime_status"`
 	EngineHealth        string  `json:"engine_health,omitempty"`
 	StartedAt           *string `json:"started_at,omitempty"`
@@ -118,6 +120,7 @@ func gameSummaryToWire(g lobby.GameRecord) gameSummaryWire {
 		EnrollmentEndsAt: g.EnrollmentEndsAt.UTC().Format(timestampLayout),
 		CreatedAt:        g.CreatedAt.UTC().Format(timestampLayout),
 		UpdatedAt:        g.UpdatedAt.UTC().Format(timestampLayout),
+		CurrentTurn:      g.RuntimeSnapshot.CurrentTurn,
 	}
 	if g.OwnerUserID != nil {
 		s := g.OwnerUserID.String()
@@ -135,7 +138,6 @@ func lobbyGameDetailToWire(g lobby.GameRecord) lobbyGameDetailWire {
 		TargetEngineVersion: g.TargetEngineVersion,
 		StartGapHours:       g.StartGapHours,
 		StartGapPlayers:     g.StartGapPlayers,
-		CurrentTurn:         g.RuntimeSnapshot.CurrentTurn,
 		RuntimeStatus:       g.RuntimeSnapshot.RuntimeStatus,
 		EngineHealth:        g.RuntimeSnapshot.EngineHealth,
 	}

backend/internal/server/handlers_user_mail.go

@@ -0,0 +1,663 @@
+package server
+
+import (
+	"context"
+	"errors"
+	"net/http"
+
+	"galaxy/backend/internal/diplomail"
+	"galaxy/backend/internal/lobby"
+	"galaxy/backend/internal/server/clientip"
+	"galaxy/backend/internal/server/handlers"
+	"galaxy/backend/internal/server/httperr"
+	"galaxy/backend/internal/server/middleware/userid"
+	"galaxy/backend/internal/telemetry"
+	"galaxy/backend/internal/user"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// UserMailHandlers groups the diplomatic-mail handlers under
+// `/api/v1/user/games/{game_id}/mail/*` and the lobby-side
+// `/api/v1/user/lobby/mail/unread-counts`. Stage A wires the
+// personal subset; Stage B adds the owner-only admin send path,
+// which needs `*lobby.Service` to confirm ownership and `*user.Service`
+// to resolve the owner's `user_name` for the `sender_username` column.
+type UserMailHandlers struct {
+	svc    *diplomail.Service
+	lobby  *lobby.Service
+	users  *user.Service
+	logger *zap.Logger
+}
+
+// NewUserMailHandlers constructs the handler set. svc may be nil — in
+// that case every handler returns 501 not_implemented. lobby and
+// users are optional: when either is nil the admin-send handler
+// degrades to 501 (the personal-send and read paths stay functional).
+func NewUserMailHandlers(svc *diplomail.Service, lobbySvc *lobby.Service, users *user.Service, logger *zap.Logger) *UserMailHandlers {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	return &UserMailHandlers{
+		svc:    svc,
+		lobby:  lobbySvc,
+		users:  users,
+		logger: logger.Named("http.user.mail"),
+	}
+}
+
+// preferredLanguage looks up the caller's `accounts.preferred_language`
+// so the per-message read can attach the cached translation when
+// available. Failures are logged at debug level and the function
+// returns an empty string — translation is best-effort and the
+// caller still receives the original body.
+func (h *UserMailHandlers) preferredLanguage(ctx context.Context, userID uuid.UUID) string {
+	if h.users == nil {
+		return ""
+	}
+	account, err := h.users.GetAccount(ctx, userID)
+	if err != nil {
+		h.logger.Debug("resolve preferred_language failed",
+			zap.String("user_id", userID.String()),
+			zap.Error(err))
+		return ""
+	}
+	return account.PreferredLanguage
+}
+
+// SendPersonal handles POST /api/v1/user/games/{game_id}/mail/messages.
+func (h *UserMailHandlers) SendPersonal() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailSendPersonal")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		var req userMailSendRequestWire
+		if err := c.ShouldBindJSON(&req); err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be valid JSON")
+			return
+		}
+		recipientID, err := uuid.Parse(req.RecipientUserID)
+		if err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "recipient_user_id must be a valid UUID")
+			return
+		}
+		ctx := c.Request.Context()
+		msg, rcpt, err := h.svc.SendPersonal(ctx, diplomail.SendPersonalInput{
+			GameID:          gameID,
+			SenderUserID:    userID,
+			RecipientUserID: recipientID,
+			Subject:         req.Subject,
+			Body:            req.Body,
+			SenderIP:        clientip.ExtractSourceIP(c),
+		})
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail send personal", ctx, err)
+			return
+		}
+		c.JSON(http.StatusCreated, mailMessageDetailToWire(diplomail.InboxEntry{Message: msg, Recipient: rcpt}, true))
+	}
+}
+
+// Get handles GET /api/v1/user/games/{game_id}/mail/messages/{message_id}.
+func (h *UserMailHandlers) Get() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailGet")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		if _, ok := parseGameIDParam(c); !ok {
+			return
+		}
+		messageID, ok := parseMessageIDParam(c)
+		if !ok {
+			return
+		}
+		ctx := c.Request.Context()
+		targetLang := h.preferredLanguage(ctx, userID)
+		entry, err := h.svc.GetMessage(ctx, userID, messageID, targetLang)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail get", ctx, err)
+			return
+		}
+		c.JSON(http.StatusOK, mailMessageDetailToWire(entry, false))
+	}
+}
+
+// Inbox handles GET /api/v1/user/games/{game_id}/mail/inbox.
+func (h *UserMailHandlers) Inbox() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailInbox")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		ctx := c.Request.Context()
+		targetLang := h.preferredLanguage(ctx, userID)
+		items, err := h.svc.ListInbox(ctx, gameID, userID, targetLang)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail inbox", ctx, err)
+			return
+		}
+		out := userMailInboxListWire{Items: make([]userMailMessageDetailWire, 0, len(items))}
+		for _, e := range items {
+			out.Items = append(out.Items, mailMessageDetailToWire(e, false))
+		}
+		c.JSON(http.StatusOK, out)
+	}
+}
+
+// Sent handles GET /api/v1/user/games/{game_id}/mail/sent.
+func (h *UserMailHandlers) Sent() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailSent")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		ctx := c.Request.Context()
+		items, err := h.svc.ListSent(ctx, gameID, userID)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail sent", ctx, err)
+			return
+		}
+		out := userMailSentListWire{Items: make([]userMailSentSummaryWire, 0, len(items))}
+		for _, m := range items {
+			out.Items = append(out.Items, mailMessageSummaryToWire(m))
+		}
+		c.JSON(http.StatusOK, out)
+	}
+}
+
+// MarkRead handles POST /api/v1/user/games/{game_id}/mail/messages/{message_id}/read.
+func (h *UserMailHandlers) MarkRead() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailMarkRead")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		if _, ok := parseGameIDParam(c); !ok {
+			return
+		}
+		messageID, ok := parseMessageIDParam(c)
+		if !ok {
+			return
+		}
+		ctx := c.Request.Context()
+		rcpt, err := h.svc.MarkRead(ctx, userID, messageID)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail mark read", ctx, err)
+			return
+		}
+		c.JSON(http.StatusOK, mailRecipientStateToWire(rcpt))
+	}
+}
+
+// Delete handles DELETE /api/v1/user/games/{game_id}/mail/messages/{message_id}.
+func (h *UserMailHandlers) Delete() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailDelete")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		if _, ok := parseGameIDParam(c); !ok {
+			return
+		}
+		messageID, ok := parseMessageIDParam(c)
+		if !ok {
+			return
+		}
+		ctx := c.Request.Context()
+		rcpt, err := h.svc.DeleteMessage(ctx, userID, messageID)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail delete", ctx, err)
+			return
+		}
+		c.JSON(http.StatusOK, mailRecipientStateToWire(rcpt))
+	}
+}
+
+// SendBroadcast handles POST /api/v1/user/games/{game_id}/mail/broadcast.
+//
+// The endpoint is the paid-tier player broadcast: any player on a
+// non-`free` entitlement tier may send one personal message that
+// fans out to every other active member of the game. The result
+// rows carry `kind="personal"`, `sender_kind="player"`,
+// `broadcast_scope="game_broadcast"`. Free-tier callers see a 403.
+func (h *UserMailHandlers) SendBroadcast() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailSendBroadcast")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		var req userMailSendBroadcastRequestWire
+		if err := c.ShouldBindJSON(&req); err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be valid JSON")
+			return
+		}
+		ctx := c.Request.Context()
+		msg, recipients, err := h.svc.SendPlayerBroadcast(ctx, diplomail.SendPlayerBroadcastInput{
+			GameID:       gameID,
+			SenderUserID: userID,
+			Subject:      req.Subject,
+			Body:         req.Body,
+			SenderIP:     clientip.ExtractSourceIP(c),
+		})
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail send broadcast", ctx, err)
+			return
+		}
+		c.JSON(http.StatusCreated, mailBroadcastReceiptToWire(msg, recipients))
+	}
+}
+
+// SendAdmin handles POST /api/v1/user/games/{game_id}/mail/admin.
+//
+// Owner-only: the caller must be the owner of the private game. The
+// handler resolves the owner's `user_name` so the
+// `sender_username` column carries a useful identity, then routes to
+// SendAdminPersonal (for `target="user"`) or SendAdminBroadcast (for
+// `target="all"`). Site administrators use the separate admin route
+// in `handlers_admin_mail_send.go`.
+func (h *UserMailHandlers) SendAdmin() gin.HandlerFunc {
+	if h.svc == nil || h.lobby == nil || h.users == nil {
+		return handlers.NotImplemented("userMailSendAdmin")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		gameID, ok := parseGameIDParam(c)
+		if !ok {
+			return
+		}
+		var req userMailSendAdminRequestWire
+		if err := c.ShouldBindJSON(&req); err != nil {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "request body must be valid JSON")
+			return
+		}
+		ctx := c.Request.Context()
+
+		game, err := h.lobby.GetGame(ctx, gameID)
+		if err != nil {
+			respondLobbyError(c, h.logger, "user mail send admin: load game", ctx, err)
+			return
+		}
+		if game.OwnerUserID == nil || *game.OwnerUserID != userID {
+			httperr.Abort(c, http.StatusForbidden, httperr.CodeForbidden, "caller is not the owner of this game")
+			return
+		}
+		account, err := h.users.GetAccount(ctx, userID)
+		if err != nil {
+			respondAccountError(c, h.logger, "user mail send admin: resolve user_name", ctx, err)
+			return
+		}
+
+		switch req.Target {
+		case "", "user":
+			recipientID, parseErr := uuid.Parse(req.RecipientUserID)
+			if parseErr != nil {
+				httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "recipient_user_id must be a valid UUID")
+				return
+			}
+			callerUserID := userID
+			msg, rcpt, sendErr := h.svc.SendAdminPersonal(ctx, diplomail.SendAdminPersonalInput{
+				GameID:          gameID,
+				CallerKind:      diplomail.CallerKindOwner,
+				CallerUserID:    &callerUserID,
+				CallerUsername:  account.UserName,
+				RecipientUserID: recipientID,
+				Subject:         req.Subject,
+				Body:            req.Body,
+				SenderIP:        clientip.ExtractSourceIP(c),
+			})
+			if sendErr != nil {
+				respondDiplomailError(c, h.logger, "user mail send admin personal", ctx, sendErr)
+				return
+			}
+			c.JSON(http.StatusCreated, mailMessageDetailToWire(diplomail.InboxEntry{Message: msg, Recipient: rcpt}, true))
+		case "all":
+			callerUserID := userID
+			msg, recipients, sendErr := h.svc.SendAdminBroadcast(ctx, diplomail.SendAdminBroadcastInput{
+				GameID:         gameID,
+				CallerKind:     diplomail.CallerKindOwner,
+				CallerUserID:   &callerUserID,
+				CallerUsername: account.UserName,
+				RecipientScope: req.Recipients,
+				Subject:        req.Subject,
+				Body:           req.Body,
+				SenderIP:       clientip.ExtractSourceIP(c),
+			})
+			if sendErr != nil {
+				respondDiplomailError(c, h.logger, "user mail send admin broadcast", ctx, sendErr)
+				return
+			}
+			c.JSON(http.StatusCreated, mailBroadcastReceiptToWire(msg, recipients))
+		default:
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "target must be 'user' or 'all'")
+		}
+	}
+}
+
+// UnreadCounts handles GET /api/v1/user/lobby/mail/unread-counts.
+func (h *UserMailHandlers) UnreadCounts() gin.HandlerFunc {
+	if h.svc == nil {
+		return handlers.NotImplemented("userMailUnreadCounts")
+	}
+	return func(c *gin.Context) {
+		userID, ok := userid.FromContext(c.Request.Context())
+		if !ok {
+			httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "X-User-ID header is required")
+			return
+		}
+		ctx := c.Request.Context()
+		items, err := h.svc.UnreadCountsForUser(ctx, userID)
+		if err != nil {
+			respondDiplomailError(c, h.logger, "user mail unread counts", ctx, err)
+			return
+		}
+		out := userMailUnreadCountsResponseWire{Items: make([]userMailUnreadCountWire, 0, len(items))}
+		total := 0
+		for _, u := range items {
+			out.Items = append(out.Items, userMailUnreadCountWire{
+				GameID:   u.GameID.String(),
+				GameName: u.GameName,
+				Unread:   u.Unread,
+			})
+			total += u.Unread
+		}
+		out.Total = total
+		c.JSON(http.StatusOK, out)
+	}
+}
+
+// respondDiplomailError maps diplomail-package sentinels to the
+// standard JSON error envelope. Unknown errors land on a 500.
+func respondDiplomailError(c *gin.Context, logger *zap.Logger, op string, ctx context.Context, err error) {
+	switch {
+	case errors.Is(err, diplomail.ErrInvalidInput):
+		httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, err.Error())
+	case errors.Is(err, diplomail.ErrNotFound):
+		httperr.Abort(c, http.StatusNotFound, httperr.CodeNotFound, "resource was not found")
+	case errors.Is(err, diplomail.ErrForbidden):
+		httperr.Abort(c, http.StatusForbidden, httperr.CodeForbidden, err.Error())
+	case errors.Is(err, diplomail.ErrConflict):
+		httperr.Abort(c, http.StatusConflict, httperr.CodeConflict, err.Error())
+	default:
+		logger.Error(op+" failed",
+			append(telemetry.TraceFieldsFromContext(ctx), zap.Error(err))...,
+		)
+		httperr.Abort(c, http.StatusInternalServerError, httperr.CodeInternalError, "service error")
+	}
+}
+
+// parseMessageIDParam reads `message_id` from the path. Writes a 400
+// envelope on invalid input and returns false in that case.
+func parseMessageIDParam(c *gin.Context) (uuid.UUID, bool) {
+	parsed, err := uuid.Parse(c.Param("message_id"))
+	if err != nil {
+		httperr.Abort(c, http.StatusBadRequest, httperr.CodeInvalidRequest, "message_id must be a valid UUID")
+		return uuid.Nil, false
+	}
+	return parsed, true
+}
+
+// userMailSendRequestWire mirrors the request body for SendPersonal.
+type userMailSendRequestWire struct {
+	RecipientUserID string `json:"recipient_user_id"`
+	Subject         string `json:"subject,omitempty"`
+	Body            string `json:"body"`
+}
+
+// userMailSendBroadcastRequestWire mirrors the request body for the
+// paid-tier player broadcast. There is no `target` discriminator —
+// the recipient set is always "every other active member".
+type userMailSendBroadcastRequestWire struct {
+	Subject string `json:"subject,omitempty"`
+	Body    string `json:"body"`
+}
+
+// userMailSendAdminRequestWire mirrors the request body for the
+// owner-only admin send. `target="user"` requires
+// `recipient_user_id`; `target="all"` accepts the optional
+// `recipients` scope (default `active`).
+type userMailSendAdminRequestWire struct {
+	Target          string `json:"target"`
+	RecipientUserID string `json:"recipient_user_id,omitempty"`
+	Recipients      string `json:"recipients,omitempty"`
+	Subject         string `json:"subject,omitempty"`
+	Body            string `json:"body"`
+}
+
+// userMailBroadcastReceiptWire is the response shape returned after a
+// successful broadcast. It carries the canonical message metadata
+// together with the count of materialised recipient rows so the
+// caller (UI, admin tool) can confirm the fan-out happened.
+type userMailBroadcastReceiptWire struct {
+	MessageID      string `json:"message_id"`
+	GameID         string `json:"game_id"`
+	GameName       string `json:"game_name,omitempty"`
+	Kind           string `json:"kind"`
+	SenderKind     string `json:"sender_kind"`
+	Subject        string `json:"subject,omitempty"`
+	Body           string `json:"body"`
+	BodyLang       string `json:"body_lang"`
+	BroadcastScope string `json:"broadcast_scope"`
+	CreatedAt      string `json:"created_at"`
+	RecipientCount int    `json:"recipient_count"`
+}
+
+func mailBroadcastReceiptToWire(m diplomail.Message, recipients []diplomail.Recipient) userMailBroadcastReceiptWire {
+	return userMailBroadcastReceiptWire{
+		MessageID:      m.MessageID.String(),
+		GameID:         m.GameID.String(),
+		GameName:       m.GameName,
+		Kind:           m.Kind,
+		SenderKind:     m.SenderKind,
+		Subject:        m.Subject,
+		Body:           m.Body,
+		BodyLang:       m.BodyLang,
+		BroadcastScope: m.BroadcastScope,
+		CreatedAt:      m.CreatedAt.UTC().Format(timestampLayout),
+		RecipientCount: len(recipients),
+	}
+}
+
+// userMailMessageDetailWire mirrors the unified response shape for
+// inbox listings and per-message reads. Sender identifiers are
+// optional: system messages carry neither user id nor username.
+// Translation fields are populated when a cached rendering exists
+// for the caller's `preferred_language`; the UI renders
+// `body_translated` and surfaces the original through a
+// "show original" toggle.
+type userMailMessageDetailWire struct {
+	MessageID         string  `json:"message_id"`
+	GameID            string  `json:"game_id"`
+	GameName          string  `json:"game_name,omitempty"`
+	Kind              string  `json:"kind"`
+	SenderKind        string  `json:"sender_kind"`
+	SenderUserID      *string `json:"sender_user_id,omitempty"`
+	SenderUsername    *string `json:"sender_username,omitempty"`
+	Subject           string  `json:"subject,omitempty"`
+	Body              string  `json:"body"`
+	BodyLang          string  `json:"body_lang"`
+	BroadcastScope    string  `json:"broadcast_scope"`
+	CreatedAt         string  `json:"created_at"`
+	RecipientUserID   string  `json:"recipient_user_id"`
+	RecipientUserName string  `json:"recipient_user_name,omitempty"`
+	RecipientRaceName *string `json:"recipient_race_name,omitempty"`
+	ReadAt            *string `json:"read_at,omitempty"`
+	DeletedAt         *string `json:"deleted_at,omitempty"`
+	TranslatedSubject *string `json:"translated_subject,omitempty"`
+	TranslatedBody    *string `json:"translated_body,omitempty"`
+	TranslationLang   *string `json:"translation_lang,omitempty"`
+	Translator        *string `json:"translator,omitempty"`
+}
+
+// userMailSentSummaryWire mirrors the response shape for the
+// sender-side listing. Recipient state is intentionally omitted (one
+// author may have N recipients per broadcast in later stages).
+type userMailSentSummaryWire struct {
+	MessageID      string `json:"message_id"`
+	GameID         string `json:"game_id"`
+	GameName       string `json:"game_name,omitempty"`
+	Kind           string `json:"kind"`
+	Subject        string `json:"subject,omitempty"`
+	Body           string `json:"body"`
+	BodyLang       string `json:"body_lang"`
+	BroadcastScope string `json:"broadcast_scope"`
+	CreatedAt      string `json:"created_at"`
+}
+
+type userMailInboxListWire struct {
+	Items []userMailMessageDetailWire `json:"items"`
+}
+
+type userMailSentListWire struct {
+	Items []userMailSentSummaryWire `json:"items"`
+}
+
+type userMailUnreadCountWire struct {
+	GameID   string `json:"game_id"`
+	GameName string `json:"game_name,omitempty"`
+	Unread   int    `json:"unread"`
+}
+
+type userMailUnreadCountsResponseWire struct {
+	Total int                       `json:"total"`
+	Items []userMailUnreadCountWire `json:"items"`
+}
+
+func mailMessageDetailToWire(entry diplomail.InboxEntry, justCreated bool) userMailMessageDetailWire {
+	out := userMailMessageDetailWire{
+		MessageID:         entry.MessageID.String(),
+		GameID:            entry.GameID.String(),
+		GameName:          entry.GameName,
+		Kind:              entry.Kind,
+		SenderKind:        entry.SenderKind,
+		Subject:           entry.Subject,
+		Body:              entry.Body,
+		BodyLang:          entry.BodyLang,
+		BroadcastScope:    entry.BroadcastScope,
+		CreatedAt:         entry.CreatedAt.UTC().Format(timestampLayout),
+		RecipientUserID:   entry.Recipient.UserID.String(),
+		RecipientUserName: entry.Recipient.RecipientUserName,
+	}
+	if entry.SenderUserID != nil {
+		s := entry.SenderUserID.String()
+		out.SenderUserID = &s
+	}
+	if entry.SenderUsername != nil {
+		s := *entry.SenderUsername
+		out.SenderUsername = &s
+	}
+	if entry.Recipient.RecipientRaceName != nil {
+		s := *entry.Recipient.RecipientRaceName
+		out.RecipientRaceName = &s
+	}
+	if entry.Recipient.ReadAt != nil {
+		s := entry.Recipient.ReadAt.UTC().Format(timestampLayout)
+		out.ReadAt = &s
+	}
+	if entry.Recipient.DeletedAt != nil {
+		s := entry.Recipient.DeletedAt.UTC().Format(timestampLayout)
+		out.DeletedAt = &s
+	}
+	if entry.Translation != nil {
+		tr := entry.Translation
+		subj := tr.TranslatedSubject
+		body := tr.TranslatedBody
+		lang := tr.TargetLang
+		engine := tr.Translator
+		out.TranslatedSubject = &subj
+		out.TranslatedBody = &body
+		out.TranslationLang = &lang
+		out.Translator = &engine
+	}
+	_ = justCreated
+	return out
+}
+
+func mailMessageSummaryToWire(m diplomail.Message) userMailSentSummaryWire {
+	return userMailSentSummaryWire{
+		MessageID:      m.MessageID.String(),
+		GameID:         m.GameID.String(),
+		GameName:       m.GameName,
+		Kind:           m.Kind,
+		Subject:        m.Subject,
+		Body:           m.Body,
+		BodyLang:       m.BodyLang,
+		BroadcastScope: m.BroadcastScope,
+		CreatedAt:      m.CreatedAt.UTC().Format(timestampLayout),
+	}
+}
+
+// mailRecipientStateToWire renders the recipient row after a
+// mark-read or soft-delete call. The caller only needs the per-user
+// state, not the full message body again.
+func mailRecipientStateToWire(r diplomail.Recipient) userMailRecipientStateWire {
+	out := userMailRecipientStateWire{
+		MessageID: r.MessageID.String(),
+	}
+	if r.ReadAt != nil {
+		s := r.ReadAt.UTC().Format(timestampLayout)
+		out.ReadAt = &s
+	}
+	if r.DeletedAt != nil {
+		s := r.DeletedAt.UTC().Format(timestampLayout)
+		out.DeletedAt = &s
+	}
+	return out
+}
+
+type userMailRecipientStateWire struct {
+	MessageID string  `json:"message_id"`
+	ReadAt    *string `json:"read_at,omitempty"`
+	DeletedAt *string `json:"deleted_at,omitempty"`
+}

backend/internal/server/httperr/httperr.go

@@ -23,6 +23,22 @@ const (
 	CodeMethodNotAllowed   = "method_not_allowed"
 	CodeInternalError      = "internal_error"
 	CodeServiceUnavailable = "service_unavailable"
+
+	// CodeTurnAlreadyClosed marks a user-games command or order rejection
+	// caused by the backend's turn-cutoff guard: the request arrived
+	// after the active turn started generating (runtime status
+	// `generation_in_progress` / `generation_failed` / `engine_unreachable`)
+	// and the engine no longer accepts writes for the closing turn. The
+	// caller is expected to wait for the next `game.turn.ready` push and
+	// resubmit against the new turn.
+	CodeTurnAlreadyClosed = "turn_already_closed"
+
+	// CodeGamePaused marks a user-games command or order rejection caused
+	// by the lobby-side game lifecycle: the game is in `paused`,
+	// `finished`, or any other status that does not accept writes. The
+	// caller is expected to wait for the game to resume before
+	// resubmitting.
+	CodeGamePaused = "game_paused"
 )
 
 // Body stores the inner `error` object of the standard envelope.

backend/internal/server/router.go

@@ -68,6 +68,7 @@ type RouterDependencies struct {
 	UserLobbyMy *UserLobbyMyHandlers
 	UserLobbyRaceNames *UserLobbyRaceNamesHandlers
 	UserGames *UserGamesHandlers
+	UserMail *UserMailHandlers
 	UserSessions *UserSessionsHandlers
 	AdminAdminAccounts *AdminAdminAccountsHandlers
 	AdminUsers *AdminUsersHandlers
@@ -75,6 +76,7 @@ type RouterDependencies struct {
 	AdminRuntimes *AdminRuntimesHandlers
 	AdminEngineVersions *AdminEngineVersionsHandlers
 	AdminMail *AdminMailHandlers
+	AdminDiplomail *AdminDiplomailHandlers
 	AdminNotifications *AdminNotificationsHandlers
 	AdminGeo *AdminGeoHandlers
 	InternalSessions *InternalSessionsHandlers
@@ -163,6 +165,9 @@ func withDefaultHandlers(deps RouterDependencies) RouterDependencies {
 	if deps.UserGames == nil {
 		deps.UserGames = NewUserGamesHandlers(nil, nil, deps.Logger)
 	}
+	if deps.UserMail == nil {
+		deps.UserMail = NewUserMailHandlers(nil, nil, nil, deps.Logger)
+	}
 	if deps.UserSessions == nil {
 		deps.UserSessions = NewUserSessionsHandlers(nil, deps.Logger)
 	}
@@ -184,6 +189,9 @@ func withDefaultHandlers(deps RouterDependencies) RouterDependencies {
 	if deps.AdminMail == nil {
 		deps.AdminMail = NewAdminMailHandlers(nil, deps.Logger)
 	}
+	if deps.AdminDiplomail == nil {
+		deps.AdminDiplomail = NewAdminDiplomailHandlers(nil, deps.Logger)
+	}
 	if deps.AdminNotifications == nil {
 		deps.AdminNotifications = NewAdminNotificationsHandlers(nil, deps.Logger)
 	}
@@ -255,13 +263,28 @@ func registerUserRoutes(router *gin.Engine, instruments *metrics.Instruments, de
 	my.GET("/invites", deps.UserLobbyMy.Invites())
 	my.GET("/race-names", deps.UserLobbyMy.RaceNames())
 
+	lobbyMail := lobbyGroup.Group("/mail")
+	lobbyMail.GET("/unread-counts", deps.UserMail.UnreadCounts())
+
 	raceNames := lobbyGroup.Group("/race-names")
 	raceNames.POST("/register", deps.UserLobbyRaceNames.Register())
 
 	userGames := group.Group("/games")
 	userGames.POST("/:game_id/commands", deps.UserGames.Commands())
 	userGames.POST("/:game_id/orders", deps.UserGames.Orders())
+	userGames.GET("/:game_id/orders", deps.UserGames.GetOrders())
 	userGames.GET("/:game_id/reports/:turn", deps.UserGames.Report())
+	userGames.GET("/:game_id/battles/:turn/:battle_id", deps.UserGames.Battle())
+
+	userMail := userGames.Group("/:game_id/mail")
+	userMail.POST("/messages", deps.UserMail.SendPersonal())
+	userMail.POST("/broadcast", deps.UserMail.SendBroadcast())
+	userMail.POST("/admin", deps.UserMail.SendAdmin())
+	userMail.GET("/messages/:message_id", deps.UserMail.Get())
+	userMail.POST("/messages/:message_id/read", deps.UserMail.MarkRead())
+	userMail.DELETE("/messages/:message_id", deps.UserMail.Delete())
+	userMail.GET("/inbox", deps.UserMail.Inbox())
+	userMail.GET("/sent", deps.UserMail.Sent())
 
 	userSessions := group.Group("/sessions")
 	userSessions.GET("", deps.UserSessions.List())
@@ -297,6 +320,7 @@ func registerAdminRoutes(router *gin.Engine, instruments *metrics.Instruments, d
 	games.POST("/:game_id/force-start", deps.AdminGames.ForceStart())
 	games.POST("/:game_id/force-stop", deps.AdminGames.ForceStop())
 	games.POST("/:game_id/ban-member", deps.AdminGames.BanMember())
+	games.POST("/:game_id/mail", deps.AdminDiplomail.Send())
 
 	runtimes := group.Group("/runtimes")
 	runtimes.GET("/:game_id", deps.AdminRuntimes.Get())
@@ -316,6 +340,9 @@ func registerAdminRoutes(router *gin.Engine, instruments *metrics.Instruments, d
 	mail.GET("/deliveries/:delivery_id/attempts", deps.AdminMail.ListDeliveryAttempts())
 	mail.POST("/deliveries/:delivery_id/resend", deps.AdminMail.ResendDelivery())
 	mail.GET("/dead-letters", deps.AdminMail.ListDeadLetters())
+	mail.GET("/messages", deps.AdminDiplomail.List())
+	mail.POST("/broadcast", deps.AdminDiplomail.Broadcast())
+	mail.POST("/cleanup", deps.AdminDiplomail.Cleanup())
 
 	notifications := group.Group("/notifications")
 	notifications.GET("", deps.AdminNotifications.List())

client/world/README.md

@@ -1,5 +1,12 @@
 # World rendering package
 
+> **Deprecated.** This package belongs to the deprecated
+> `galaxy/client` Fyne client. New code must not import it. The
+> active map renderer lives in `ui/frontend/src/map/` (TypeScript
+> + PixiJS), with its specification in `ui/docs/renderer.md`. The
+> sources here remain for historical context only and are not the
+> reference algorithm for the new renderer.
+
 ## Purpose
 
 `world` is the client-side map model and renderer for a 2D world that normally

docs/ARCHITECTURE.md

@@ -145,6 +145,15 @@ because they cross domain boundaries:
   `X-User-ID`. Public games carry `owner_user_id IS NULL`; the partial
   index on `(owner_user_id) WHERE visibility = 'private'` keeps the
   private-owner lookup efficient.
+- **Authenticated lobby commands** flow through the gateway envelope
+  by `message_type`. The catalog is `lobby.my.games.list`,
+  `lobby.public.games.list`, `lobby.my.applications.list`,
+  `lobby.my.invites.list`, `lobby.game.create`,
+  `lobby.game.open-enrollment`, `lobby.application.submit`,
+  `lobby.invite.redeem`, and `lobby.invite.decline`. Each lands on a
+  REST handler under `/api/v1/user/lobby/*`; the gateway forces
+  visibility to `private` on `lobby.game.create` before forwarding,
+  matching the user-surface invariant above.
 
 | Package                          | Responsibility                                                                                                                                                          |
 | -------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
@@ -183,10 +192,12 @@ because they cross domain boundaries:
   `race_name`) remain `text`.
 - Foreign keys are intra-domain only: `accounts → entitlement_*` /
   `sanction_*` / `limit_*`; `games → applications` / `invites` /
-  `memberships` (with `ON DELETE CASCADE`); `mail_payloads →
+  `memberships` / `diplomail_messages` (each with
-  mail_deliveries → mail_recipients` / `mail_attempts` /
+  `ON DELETE CASCADE`); `mail_payloads → mail_deliveries →
-  `mail_dead_letters`; `notifications → notification_routes` /
+  mail_recipients` / `mail_attempts` / `mail_dead_letters`;
-  `notification_dead_letters`. Cross-domain references
+  `notifications → notification_routes` / `notification_dead_letters`;
+  `diplomail_messages → diplomail_recipients` /
+  `diplomail_translations`. Cross-domain references
   (`memberships.user_id`, `games.owner_user_id`, etc.) are kept as
   opaque `uuid` columns because each domain runs its own cleanup
   through the in-process cascade described in [§7](#7-in-process-async-patterns). Adding a database
@@ -362,11 +373,15 @@ Authenticated client traffic for in-game operations crosses three
 serialisation boundaries: signed-gRPC FlatBuffers (client ↔ gateway),
 JSON over REST (gateway ↔ backend), and JSON over REST again
 (backend ↔ engine). Gateway owns the FB ↔ JSON transcoding for the
-three message types `user.games.command`, `user.games.order`,
+four message types `user.games.command`, `user.games.order`,
-`user.games.report` (FB schemas in `pkg/schema/fbs/{order,report}`,
+`user.games.order.get`, `user.games.report` (FB schemas in
-encoders in `pkg/transcoder`). Backend never touches FlatBuffers and
+`pkg/schema/fbs/{order,report}`, encoders in `pkg/transcoder`).
-never re-interprets the JSON beyond rebinding the actor field from
+`user.games.order.get` reads back the player's stored order for a
-the runtime player mapping (clients never carry a trusted actor).
+given turn — paired with the POST `user.games.order` so the client
+can hydrate its local draft after a cache loss without re-deriving
+from the report. Backend never touches FlatBuffers and never
+re-interprets the JSON beyond rebinding the actor field from the
+runtime player mapping (clients never carry a trusted actor).
 
 Container state is owned by `backend/internal/runtime`:
 
@@ -443,12 +458,15 @@ committed; SMTP completion is asynchronous to the auth request.
 
 Notifications are an in-process pipeline. The closed catalog is
 defined in `backend/internal/notification/catalog.go` and currently
-covers 13 kinds: 10 lobby kinds (invite received/revoked, application
+covers 16 kinds: 10 lobby kinds (invite received/revoked, application
 submitted/approved/rejected, membership removed/blocked, race name
-registered/pending/expired) and 3 admin-recipient runtime kinds
+registered/pending/expired), 3 admin-recipient runtime kinds (image
-(image pull failed, container start failed, start config invalid).
+pull failed, container start failed, start config invalid), 2 game
-Per-kind delivery channels (push, email, or both) and the admin-vs-
+lifecycle kinds (turn ready, game paused), and the
-per-user recipient routing live in the same file.
+`diplomail.message.received` kind that fans diplomatic-mail send
+events out to the recipient's push stream. Per-kind delivery channels
+(push, email, or both) and the admin-vs-per-user recipient routing
+live in the same file.
 
 For every intent, `notification.Submit` performs:
 
@@ -477,6 +495,34 @@ Notification persistence is the auditable record of "we tried to tell
 this user about this thing"; clients still derive their actual game
 state through normal user-facing reads.
 
+### 12.1 Diplomatic mail subsystem
+
+`backend/internal/diplomail` owns the player-to-player message channel
+that the in-game mail view consumes. The data lives in three tables:
+
+- `diplomail_messages` — one canonical row per send. Captures the
+  game name and the sender IP at insert time so audit rendering
+  survives game renames and bulk purges. `kind` is `personal` (a
+  replyable player→player message) or `admin` (a non-replyable
+  notification produced by an administrator or the system).
+  `sender_kind` distinguishes `player`, `admin`, and `system` senders.
+  `broadcast_scope` carries `single`, `game_broadcast`, or
+  `multi_game_broadcast`.
+- `diplomail_recipients` — one row per (message, recipient). Holds
+  the per-user `read_at`, `deleted_at`, `delivered_at`, `notified_at`
+  state plus snapshot fields (`recipient_user_name`,
+  `recipient_race_name`) so admin search and the inbox listing render
+  correctly even after the source rows are renamed or revoked.
+- `diplomail_translations` — cached per-language rendering shared
+  across every recipient with the same `accounts.preferred_language`.
+
+Stage A wires the personal subset (single recipient, no language
+detection). Lifecycle hooks (paused / cancelled / kicked), paid-tier
+player broadcasts, multi-game admin broadcasts, bulk purge, and the
+detection / translation cache land in later stages. The package is
+the only place that constructs `diplomail.message.received` push
+intents; the notification pipeline takes it from there.
+
 ## 13. Container Lifecycle (in-process)
 
 `backend/internal/runtime` owns the lifecycle of game-engine containers
@@ -531,6 +577,15 @@ This section describes the secure exchange model between client and
 gateway. It applies at the public boundary and does not rely on backend
 behaviour for any of its guarantees.
 
+The authenticated edge listener is built on `connectrpc.com/connect` and
+natively serves the Connect, gRPC, and gRPC-Web protocols on a single
+HTTP/2 cleartext (`h2c`) port. Browser clients use Connect via
+`@connectrpc/connect-web`; native iOS / Android / desktop clients can
+use either Connect or raw gRPC framing against the same listener.
+Envelope, signature, freshness, and anti-replay rules below are
+protocol-agnostic — they apply identically to every supported wire
+framing.
+
 ### Principles
 
 - No browser cookies.
@@ -563,7 +618,9 @@ and revoke metadata.
   the device.
 - Browser/WASM clients use WebCrypto with non-exportable storage where
   available. Loss of browser storage is acceptable and is recovered by
-  re-login.
+  re-login. The concrete browser baseline, IndexedDB schema, and
+  keystore lifecycle live in
+  [`ui/docs/storage.md`](../ui/docs/storage.md).
 
 ### Request envelope
 
@@ -727,7 +784,50 @@ addition.
   `GET /readyz` (Postgres reachable, migrations applied, gRPC listener
   bound). Probes are excluded from anti-replay and rate limiting.
 
-## 18. Deployment Topology (informational)
+## 18. CI and Environments
+
+The repository is monorepo and intentionally so — semver tags and
+per-service rollouts are achievable without splitting the code into
+multiple repositories.
+
+Branches:
+
+- `main` — production-track. Direct pushes are disallowed; the only
+  way in is a PR merge from `development`.
+- `development` — long-lived dev integration branch. Every merge
+  triggers an auto-deploy into the long-lived dev environment on the
+  CI host, reachable through the host Caddy at
+  `https://www.galaxy.lan` and `https://api.galaxy.lan`.
+- `feature/*` — short-lived branches off `development`. Merged back
+  via PR; PRs run unit + integration checks before merge.
+
+Workflows under `.gitea/workflows/`:
+
+| File | Trigger | Purpose |
+|------|---------|---------|
+| `go-unit.yaml` | push + PR matching Go paths | Fast Go unit tests. |
+| `ui-test.yaml` | push + PR matching `ui/**` | Vitest + Playwright. |
+| `integration.yaml` | PR to `development` / `main`; push to `development` | testcontainers integration suite. |
+| `dev-deploy.yaml` | push to `development` | Build images, seed UI volume, `compose up` against `tools/dev-deploy/`. |
+| `prod-build.yaml` | push to `main` | Build production images and persist `docker save` bundles as artifacts. |
+| `deploy-prod.yaml` | manual `workflow_dispatch` | Placeholder for the future SSH-based production rollout. |
+
+Environments:
+
+- **`tools/local-dev/`** — single-developer playground. Bound to
+  host ports, Vite dev server runs on the host. Not driven by CI.
+- **`tools/dev-deploy/`** — long-lived dev environment behind
+  `*.galaxy.lan`, redeployed on every merge into `development`.
+- **production** — future. Images come from the
+  `galaxy-images-commit-<sha>` artifact produced by `prod-build.yaml`
+  and are shipped to the production host via `docker save` →
+  `ssh prod docker load` → `docker compose up -d`.
+
+`tools/local-ci/` remains as an opt-in fallback runner for testing
+workflow changes without `gitea.lan`. It is no longer part of the
+per-stage CI gate; see `CLAUDE.md` for the gate definition.
+
+## 19. Deployment Topology (informational)
 
 - MVP runs three executables: one `gateway` instance, one `backend`
   instance, and N `galaxy-game-{game_id}` containers managed by backend.
@@ -746,7 +846,7 @@ Future scale-out hooks (not in MVP):
 - mTLS between gateway and backend.
 - Docker-socket-proxy sidecar fronting Docker daemon access.
 
-## 19. Glossary
+## 20. Glossary
 
 - **device_session_id** — opaque identifier of an authenticated client
   device; primary key of the device session record.
@@ -761,9 +861,21 @@ Future scale-out hooks (not in MVP):
 - **runtime snapshot** — engine-status read materialised into the lobby's
   denormalised view: `current_turn`, `runtime_status`,
   `engine_health_summary`, `player_turn_stats`.
-- **turn cutoff** — the `running → generation_in_progress` CAS transition
+- **turn cutoff** — the `running → generation_in_progress` runtime-status
-  that closes the command window. Commands arriving after the CAS are
+  flip performed by `backend/internal/runtime/scheduler.go` before each
-  rejected.
+  engine `/admin/turn` call. Commands and orders arriving while the
+  flag is set are rejected by the user-games handlers with HTTP 409
+  `turn_already_closed`. The matching reopening flip
+  (`generation_in_progress → running`) happens on a successful tick;
+  a failing tick instead drives the lobby to `paused` and fans out
+  `game.paused` (FUNCTIONAL.md §6.3, §6.5).
+- **auto-pause** — the lobby reaction to a failed runtime snapshot
+  (`engine_unreachable` / `generation_failed`): the game flips
+  `running → paused`, the order handlers refuse new submits with
+  HTTP 409 `game_paused`, and `lobby.publishGamePaused` fans out the
+  push event. Only an admin `/resume` followed by a successful tick
+  recovers the game; the UI relies on the next `game.turn.ready` to
+  clear the paused banner.
 - **outbox** — the durable queue of pending mail rows in
   `mail_deliveries`, drained by the mail worker.
 - **freshness window** — the symmetric ±5-minute interval around server

docs/FUNCTIONAL.md

@@ -47,6 +47,7 @@ same scenario when they participate in the same business flow.
 8. [Notifications and mail](#8-notifications-and-mail)
 9. [Geo signal](#9-geo-signal)
 10. [Administration](#10-administration)
+11. [Diplomatic mail](#11-diplomatic-mail)
 
 ---
 
@@ -100,12 +101,15 @@ Branches inside backend:
   new one. The client gets the same response shape and is unaware of
   the reuse.
 - **Otherwise.** Backend creates a new challenge with the resolved
-  preferred language (derived from the optional `Accept-Language`
+  preferred language (derived from the optional `locale` body field
-  header forwarded by gateway, falling back to a default), and
+  the caller sends — which takes priority — or, if absent or blank,
-  enqueues the auth-mail row directly into the outbox in the same
+  from the `Accept-Language` header forwarded by gateway, falling
-  transaction. SMTP delivery is asynchronous; the auth response
+  back to a default), and enqueues the auth-mail row directly into
-  returns as soon as the challenge and outbox rows are durably
+  the outbox in the same transaction. SMTP delivery is asynchronous;
-  committed.
+  the auth response returns as soon as the challenge and outbox rows
+  are durably committed. The body field is the canonical channel
+  because Safari silently drops JS-set `Accept-Language` headers;
+  non-Safari clients can still rely on the header alone.
 
 ### 1.3 Confirming the challenge
 
@@ -139,9 +143,10 @@ consumed exactly once.
 ### 1.4 Per-request session lookup
 
 Once the client holds a device session id and a private key, every
-authenticated call is a signed gRPC request to gateway. Gateway is the
+authenticated call is a signed request to gateway over the
-only component that ever sees the request signature; backend trusts
+authenticated edge listener (Connect / gRPC / gRPC-Web on a single
-gateway's verdict.
+HTTP/h2c port). Gateway is the only component that ever sees the
+request signature; backend trusts gateway's verdict.
 
 Gateway needs the session's public key to verify the signature, so each
 authenticated request resolves the device session through an in-memory
@@ -602,13 +607,16 @@ not duplicated here.
 
 ### 6.2 Backend's role: pass-through with authorisation
 
-The signed-gRPC pipeline for in-game traffic uses three message types
+The signed authenticated-edge pipeline for in-game traffic uses four
-on the authenticated surface — `user.games.command`,
+message types on the authenticated surface — `user.games.command`,
-`user.games.order`, `user.games.report` — each with a typed
+`user.games.order`, `user.games.order.get`, `user.games.report` —
-FlatBuffers payload. Gateway transcodes the FB request into the JSON
+each with a typed FlatBuffers payload. Gateway transcodes the FB
-shape backend expects, forwards over plain REST to the corresponding
+request into the JSON shape backend expects, forwards over plain
-`/api/v1/user/games/{game_id}/*` endpoint, then transcodes the JSON
+REST to the corresponding `/api/v1/user/games/{game_id}/*` endpoint,
-response back into FB before signing the reply.
+then transcodes the JSON response back into FB before signing the
+reply. `user.games.order.get` is the read-back companion to
+`user.games.order`: clients use it to hydrate the local order draft
+after a cache loss (fresh install, cleared storage, new device).
 
 For every in-game endpoint the user surface acts as an authorised
 pass-through to the engine container. Backend:
@@ -628,18 +636,40 @@ validity and ordering of in-game decisions. Gateway needs to know
 the typed FB shape only to transcode the wire format; the per-command
 semantics live in the engine.
 
-### 6.3 Turn cutoff
+### 6.3 Turn cutoff and auto-pause
 
 A running game continuously alternates between a command-accepting
-window and a generation phase. The transition `running →
+window and a generation phase, driven by the cron expression stored
-generation_in_progress` is the cutoff: any command or order that
+in `runtime_records.turn_schedule`. The backend scheduler
-arrives after the cutoff is rejected by backend before forwarding,
+(`backend/internal/runtime/scheduler.go`) wraps each engine
-because the engine no longer accepts writes for the closing turn.
+`/admin/turn` call between two `runtime_status` flips:
-After generation finishes, backend re-opens the window for the next
+
-turn.
+- Before the engine call: `running → generation_in_progress`.
+  The user-games command/order handlers
+  (`backend/internal/server/handlers_user_games.go`) consult the
+  per-game runtime record on every request and reject with
+  HTTP 409 + `code = turn_already_closed` while the runtime sits in
+  `generation_in_progress`. The error envelope mirrors backend's
+  standard `httperr` shape: `{"error": {"code":
+  "turn_already_closed", "message": "..."}}`.
+- After a successful tick: `generation_in_progress → running`.
+  The order window re-opens for the new turn and the next
+  scheduled tick continues normally.
+- After a failed tick (`engine_unreachable` /
+  `generation_failed`): the lobby's `OnRuntimeSnapshot` flips the
+  game from `running` to `paused` and publishes a `game.paused`
+  push event (see §6.6). The order handlers reject with HTTP 409
+  + `code = game_paused` until an admin resume succeeds.
 
 `force-next-turn` (admin) schedules a one-shot extra tick that
-advances the next scheduled turn by one cron step.
+advances the next scheduled turn by one cron step; the same
+status-flip and rejection rules apply.
+
+Clients distinguish the two rejections by `code`:
+`turn_already_closed` means "wait for the next `game.turn.ready`
+and resubmit", whereas `game_paused` means "wait for an admin
+resume". The web client implements both reactions in
+`ui/docs/sync-protocol.md`.
 
 ### 6.4 Reports
 
@@ -647,7 +677,79 @@ Per-turn reports are read-only views fetched from the engine on
 demand. Backend authorises the caller and forwards the request;
 there is no caching or denormalisation in this path.
 
-### 6.5 Side effects
+The web client renders the report as one section per FBS array
+(galaxy summary, votes, player status, my / foreign sciences, my /
+foreign ship classes, battles, bombings, approaching groups, my /
+foreign / uninhabited / unknown planets, ships in production,
+cargo routes, my fleets, my / foreign / unidentified ship groups).
+Empty sections render explicit empty-state copy. Section anchors
+are exposed in a sticky table of contents (a `<select>` on mobile)
+and the scroll position is preserved across active-view switches
+via SvelteKit's `Snapshot` API.
+
+The Bombings section is a flat read-only table — one row per
+bombing event, columns for `attacker`, `attack_power`, `wiped`
+state and the post-bombing resource snapshot. The Battles section
+is a list of links into the Battle Viewer (see [§6.5](#65-battle-viewer)).
+
+### 6.5 Battle viewer
+
+The Battle Viewer is a dedicated view that replaces the map and
+renders one battle at a time. Entry points:
+
+- A row in the Reports view's Battles section (link with the
+  current turn pinned via `?turn=`).
+- A battle marker on the map (yellow cross drawn through the
+  corners of the square that circumscribes the planet circle;
+  stroke width scales with the protocol length).
+
+The viewer is a logically isolated component that consumes a
+`BattleReport` (shape per `pkg/model/report/battle.go`). The page
+loader (`ui/frontend/src/lib/active-view/battle.svelte`) fetches
+the report through the backend gateway route
+`GET /api/v1/user/games/{game_id}/battles/{turn}/{battle_id}`,
+which forwards verbatim to the engine's
+`GET /api/v1/battle/:turn/:uuid`.
+
+Visual model is radial: the planet sits at the centre, races are
+placed at equal angular spacing on an outer ring, and each race is
+rendered as a cloud of ship-class circles arranged on a Vogel
+sunflower spiral biased toward the planet (the largest group by
+NumberLeft sits closest to the planet, lighter buckets fan behind).
+Tech-variants of the same `(race, className)` collapse into one
+visual bucket labelled `<className>:<numLeft>`; per-class detail
+stays available in the Reports view. Circle radius scales with
+per-ship FullMass (range `[6, 24] px`, per-battle normalisation)
+so heavy ships visually dominate. Observer groups (`inBattle:
+false`) are not drawn. Eliminated races drop out and the survivors
+re-spread on the next frame. The viewer is pinned to the viewport
+(scene grows, log scrolls internally) so no page-level scroll
+appears.
+
+Each frame is one protocol entry; the shot is drawn as a thin line
+from attacker to defender, red on `destroyed`, green otherwise.
+Continuous playback offers 1x / 2x / 4x speeds (400 / 200 / 100 ms
+per frame), plus play/pause, step ±, and rewind. The accessibility
+text protocol below the scene mirrors the same events line-by-line.
+
+Bombings and battles are intentionally not mixed: bombings remain a
+static table in the Reports view; the bombing marker on the map is
+a thin stroke-only ring around the planet (yellow when damaged, red
+when wiped) and a click scrolls the corresponding row into view.
+
+The current report wire carries a `battle: [{ id, planet, shots }]`
+summary per battle so the map markers know where to anchor without
+fetching every full `BattleReport`.
+
+For DEV / e2e the legacy-report CLI
+(`tools/local-dev/legacy-report/cmd/legacy-report-to-json`) emits an
+envelope `{version: 1, report, battles}` where `battles` carries the
+full `BattleReport`-s parsed out of legacy `Battle at (#N)` blocks.
+The synthetic-report loader on the lobby unwraps the envelope and
+hands every battle to `registerSyntheticBattle`, so the Battle Viewer
+resolves any UUID without a network fetch.
+
+### 6.6 Side effects
 
 A successful turn generation publishes a runtime snapshot into the
 lobby module, which updates the denormalised view (current turn,
@@ -655,15 +757,32 @@ runtime status, per-player stats). The engine's "game finished"
 report drives the `running → finished` transition ([Section 3.5](#35-cancellation-and-finish))
 and triggers Race Name Directory promotions ([Section 5](#5-race-name-directory)).
 
-The `game.*` notification kinds (`game.started`, `game.turn.ready`,
+Among the `game.*` notification kinds, `game.turn.ready` and
-`game.generation.failed`, `game.finished`) are reserved in the
+`game.paused` are wired:
-documentation but have **no producer** in the codebase today; the
-notification catalog explicitly omits them (`backend/internal/notification/catalog.go`).
-Adding a producer is purely additive: register the kind in the
-catalog, populate `MailTemplateID` if email fan-out is desired, and
-have the appropriate domain module call `notification.Submit`.
 
-### 6.6 Cross-references
+- `game.turn.ready` —
+  `lobby.Service.OnRuntimeSnapshot` (`backend/internal/lobby/runtime_hooks.go`)
+  emits one intent per advancing `current_turn`, addressed to every
+  active membership of the game, with idempotency key
+  `turn-ready:<game_id>:<turn>` and JSON payload `{game_id, turn}`.
+- `game.paused` — the same hook publishes one intent per transition
+  into `paused` driven by an `engine_unreachable` /
+  `generation_failed` runtime snapshot, addressed to every active
+  membership, with idempotency key `paused:<game_id>:<turn>` and
+  JSON payload `{game_id, turn, reason}`. The runtime status that
+  triggered the transition is carried as `reason` so the UI can
+  differentiate the copy in a future revision.
+
+Both kinds route through the push channel only; email is
+deliberately omitted to avoid per-turn / per-pause spam.
+
+The remaining `game.*` kinds (`game.started`, `game.generation.failed`,
+`game.finished`) and `mail.dead_lettered` are reserved without a
+producer; adding one is purely additive (register the kind in the
+catalog, extend the migration `CHECK` constraint, and call
+`notification.Submit` from the appropriate domain module).
+
+### 6.7 Cross-references
 
 - Backend ↔ engine wire contract (`pkg/model/{order,report,rest}`):
   [ARCHITECTURE.md §9](ARCHITECTURE.md#9-backend--game-engine-communication).
@@ -680,9 +799,10 @@ session invalidations).
 
 ### 7.1 Scope
 
-In scope: the gRPC stream a client opens against gateway, the
+In scope: the server-streaming subscription a client opens against
-bootstrap event, the framing of forwarded events, and the
+gateway (Connect / gRPC / gRPC-Web framing all map to the same
-backend → gateway control channel that produces those events.
+endpoint), the bootstrap event, the framing of forwarded events, and
+the backend → gateway control channel that produces those events.
 
 Out of scope: the catalog of event kinds — see [Section 8](#8-notifications-and-mail) for the
 notification side and [`backend/README.md` §10](../backend/README.md#10-notification-catalog) for the closed list.
@@ -1034,3 +1154,223 @@ counters are populated by the runtime, and operators can only read.
 - Mail outbox and notification dispatcher:
   [ARCHITECTURE.md §11](ARCHITECTURE.md#11-mail-outbox),
   [§12](ARCHITECTURE.md#12-notification-pipeline) and [Section 8](#8-notifications-and-mail).
+
+---
+
+## 11. Diplomatic mail
+
+This scenario covers the player-to-player and admin-to-player
+messaging system exposed inside a game. The system is conceptually
+part of the lobby (messages outlive game runtime restarts), but
+they are surfaced exclusively inside the in-game UI; the lobby
+surfaces only an unread counter.
+
+### 11.1 Scope
+
+In scope: sending personal mail between active members of the same
+game; replying to personal mail; reading and marking-read /
+soft-deleting one's own incoming mail; admin / owner notifications
+addressed to one player or broadcast to a game; paid-tier player
+broadcasts; site-admin multi-game broadcasts; bulk purge of
+messages tied to terminated games; auto-translation of the body
+into the recipient's `preferred_language` with a cached rendering.
+
+Out of scope: out-of-game chat, group chats spanning multiple
+games, file attachments, message editing or unsend, end-to-end
+encryption.
+
+### 11.2 The message model
+
+Every send produces exactly one row in `diplomail_messages` plus
+one row per recipient in `diplomail_recipients`. A broadcast to N
+recipients is one message + N recipient rows; the translation row,
+when materialised, is shared across every recipient with the same
+target language.
+
+`diplomail_messages.kind` is the closed set
+`{personal, admin}`. Personal messages are replyable (the
+recipient sends back a new personal message); admin messages are
+non-replyable acknowledgements of a state change or operator
+action. `sender_kind` is `{player, admin, system}` and identifies
+the originator's role: a player owns the game (admin notification
+from owner), a site administrator pushed it (admin notification
+from operator), or the lobby state machine produced it
+(`game.paused`, `game.cancelled`, `membership.removed`,
+`membership.blocked`).
+
+`broadcast_scope` records whether the send was a single-recipient
+delivery (`single`), a one-game broadcast (`game_broadcast`), or a
+cross-game admin broadcast (`multi_game_broadcast`). Recipients of
+a multi-game broadcast see one independently-deletable inbox entry
+per game they were addressed in.
+
+Per-row snapshots travel with each message: `game_name`,
+`sender_username`, `sender_ip`, plus on the recipient row
+`recipient_user_name`, `recipient_race_name`, and
+`recipient_preferred_language`. These survive game-name changes,
+membership revocation, account soft-delete, and the eventual
+bulk-purge cascade — they let the admin observability surface
+render correctly long after the live rows have moved on.
+
+Bodies and subjects are plain UTF-8 text. The server does not
+parse, sanitise, or escape HTML; the client renders bodies through
+`textContent`. Maximum body size is
+`BACKEND_DIPLOMAIL_MAX_BODY_BYTES` (default `4096`); maximum
+subject size is `BACKEND_DIPLOMAIL_MAX_SUBJECT_BYTES` (default
+`256`).
+
+### 11.3 Sending mail
+
+Personal sends require active membership in the game for both the
+sender and the recipient. Free-tier players send one personal
+message per request. Paid-tier players additionally have access to
+a game-scoped broadcast that addresses every other active member
+in one call; replies fan back to the broadcast author.
+
+Game owners (of private games) and site administrators send admin
+notifications. The owner endpoint lives under the user surface
+(authenticated by `X-User-ID`, owner check enforced); the admin
+endpoint lives under the admin surface (HTTP Basic). Both accept
+`target=user` (single recipient) or `target=all` (game broadcast).
+Site administrators additionally have a multi-game endpoint that
+accepts `scope=selected` with a list of game ids or
+`scope=all_running` that enumerates every game with non-terminal
+status.
+
+Broadcast composition is parameterised by `recipients`: `active`
+(default), `active_and_removed`, or `all_members` (includes
+blocked rows for audit-style mail). The broadcast author's own
+recipient row is never created.
+
+A paid-tier broadcast is rejected with `403 forbidden` when the
+caller's entitlement tier is `free`.
+
+### 11.4 Receiving mail
+
+The recipient sees the message in their in-game inbox once the
+async translation worker has finished processing it (see
+[§11.6](#116-translation)). Until then the row stays invisible:
+absent from the inbox listing, not counted in the unread badge, no
+push event delivered. This avoids a surprise where the inbox shows
+a row with no translation and an outdated unread count.
+
+The unread badge in the lobby aggregates by game. The
+`/api/v1/user/lobby/mail/unread-counts` endpoint returns one entry
+per game with non-zero unread plus the global total; the lobby UI
+renders the total badge and a per-game tile counter without
+exposing the messages themselves.
+
+Marking a message as read is idempotent. Soft-deletion requires the
+message to already be marked read — a client cannot erase an
+unopened message. Soft-deletion is per-recipient: the underlying
+message row survives until the admin bulk-purge endpoint removes
+the entire game's mail tree.
+
+The message detail response includes both the original body and,
+when available, the cached translation; the client UI defaults to
+the translated text and offers a "show original" toggle.
+
+### 11.5 Lifecycle hooks
+
+Three lobby transitions land as system mail in the affected
+players' inboxes:
+
+- **Game paused / cancelled.** When the game state machine moves
+  through `paused` or `cancelled`, the lobby emits a system mail
+  addressed to every active member. The message explains the
+  transition with a server-rendered template, so even an offline
+  player finds the context the next time they open the inbox.
+- **Membership removed / blocked.** Manual self-leave, owner-driven
+  removal, and admin ban each emit a system mail addressed to the
+  affected player only. This mail survives the membership going
+  to `removed` / `blocked`, so a kicked player keeps read access
+  to the explanation forever (soft-access rule).
+
+Future inactivity-driven removal must call the same publisher so
+the explanation reaches the affected player; the lobby package
+README pins this contract for the next implementer.
+
+### 11.6 Translation
+
+`diplomail_messages.body_lang` is filled at send time by an
+in-process language detector that operates on the body only.
+Subject inherits the body's detected language for the translation
+cache lookup. When detection cannot confidently label the body
+(too short, empty, mixed scripts) the value is the BCP 47
+`und` ("undetermined") sentinel and the translation pipeline is
+short-circuited — recipients receive the original.
+
+Translation happens asynchronously. Every recipient row stores a
+snapshot of the addressee's `preferred_language` plus an
+`available_at` timestamp. A recipient whose language matches the
+detected `body_lang` (or whose preferred language is empty / the
+body language is `und`) gets `available_at = now()` on insert and
+the push event fires immediately. A recipient whose language
+differs is inserted with `available_at IS NULL` and waits for the
+translation worker.
+
+The worker (`internal/diplomail.Worker`) ticks every
+`BACKEND_DIPLOMAIL_WORKER_INTERVAL` (default `2s`) and processes
+one `(message_id, target_lang)` pair per tick. It consults the
+translation cache first; on miss it asks the configured
+`Translator`. The default deployment ships the LibreTranslate HTTP
+client; an empty `BACKEND_DIPLOMAIL_TRANSLATOR_URL` falls back to
+the noop translator that delivers every message in the original
+language.
+
+Translation outcomes:
+
+- **Success.** A row in `diplomail_translations` is inserted (or
+  reused if another worker won the race), every pending recipient
+  of the pair is flipped to `available_at = now()`, and one push
+  event per recipient is published.
+- **Unsupported language pair** (HTTP 400 from LibreTranslate).
+  No translation row is persisted; recipients are delivered with
+  the original body. Subsequent reads return the original.
+- **Transient failure** (timeout, 5xx, network error). The
+  attempt counter is bumped and the next attempt is scheduled via
+  exponential backoff `1s → 2s → 4s → 8s → 16s` (capped at 60s).
+  After `BACKEND_DIPLOMAIL_TRANSLATOR_MAX_ATTEMPTS` (default `5`)
+  the worker falls back to delivering the original body. A
+  prolonged translator outage therefore stalls delivery by at
+  most ~30 seconds per pair before the receiver sees the
+  original.
+
+The translation cache is shared: a broadcast to N recipients with
+the same preferred language produces one cache row and one
+translator call, not N.
+
+### 11.7 Storage and purge
+
+Messages live in `diplomail_messages`; per-recipient state lives
+in `diplomail_recipients` with a foreign-key cascade to the
+message; translations live in `diplomail_translations` also with a
+cascade. The sender IP is captured at insert time from
+`X-Forwarded-For` (forwarded by gateway) for evidence preservation.
+
+There is no automatic retention. The admin bulk-purge endpoint
+removes every message whose game finished more than
+`older_than_years` years ago (minimum `1`); the cascade drops the
+recipient and translation rows in the same transaction.
+
+### 11.8 Operator visibility
+
+The admin surface exposes a paginated listing of every persisted
+message (`/api/v1/admin/mail/messages`) filterable by `game_id`,
+`kind`, and `sender_kind`. The bulk-purge endpoint
+(`/api/v1/admin/mail/cleanup`) accepts the `older_than_years`
+threshold. Per-game admin sends and multi-game broadcasts live
+under `/api/v1/admin/games/{game_id}/mail` and
+`/api/v1/admin/mail/broadcast`.
+
+### 11.9 Cross-references
+
+- Package overview and stage map:
+  [`backend/internal/diplomail/README.md`](../backend/internal/diplomail/README.md).
+- LibreTranslate setup recipe for local development:
+  [`backend/docs/diplomail-translator-setup.md`](../backend/docs/diplomail-translator-setup.md).
+- Storage detail:
+  [ARCHITECTURE.md §12.1](ARCHITECTURE.md#121-diplomatic-mail-subsystem).
+- Push transport for delivery events: [Section 7](#7-push-channel).
+- Notification catalog kind `diplomail.message.received`:
+  [`backend/README.md` §10](../backend/README.md#10-notification-catalog).

docs/FUNCTIONAL_ru.md

@@ -47,6 +47,7 @@ field-level-валидация — всё это лежит в нижнеуро
 8. [Уведомления и почта](#8-уведомления-и-почта)
 9. [Гео-сигнал](#9-гео-сигнал)
 10. [Администрирование](#10-администрирование)
+11. [Дипломатическая почта](#11-дипломатическая-почта)
 
 ---
 
@@ -99,11 +100,15 @@ Backend выпускает непрозрачный идентификатор
   backend переиспользует последний имеющийся вызов вместо создания
   нового. Клиент получает ту же форму ответа и не знает о повторе.
 - **Иначе.** Backend создаёт новый вызов с разрешённым preferred_language
-  (выводится из опционального заголовка `Accept-Language`,
+  (выводится из опционального поля `locale` в JSON-теле — оно имеет
-  форварднутого gateway, с откатом на дефолт) и в той же транзакции
+  приоритет — либо, если оно отсутствует или пустое, из заголовка
-  ставит auth-mail-строку прямо в outbox. SMTP-доставка асинхронна;
+  `Accept-Language`, форварднутого gateway, с откатом на дефолт) и
-  auth-ответ возвращается, как только строки challenge и outbox
+  в той же транзакции ставит auth-mail-строку прямо в outbox.
-  durably закоммитены.
+  SMTP-доставка асинхронна; auth-ответ возвращается, как только
+  строки challenge и outbox durably закоммитены. Поле в теле — это
+  канонический канал, потому что Safari молча сбрасывает выставляемые
+  из JS заголовки `Accept-Language`; клиентам не на Safari достаточно
+  одного заголовка.
 
 ### 1.3 Подтверждение вызова
 
@@ -138,9 +143,10 @@ Throttle-переиспользование на стороне send означ
 ### 1.4 Поиск сессии для каждого запроса
 
 Когда у клиента есть идентификатор устройства-сессии и приватный ключ,
-каждый аутентифицированный вызов — это подписанный gRPC-запрос к
+каждый аутентифицированный вызов — это подписанный запрос к gateway
-gateway. Gateway — единственный компонент, который видит подпись
+по аутентифицированному edge-листенеру (Connect / gRPC / gRPC-Web на
-запроса; backend доверяет вердикту gateway.
+одном HTTP/h2c-порту). Gateway — единственный компонент, который видит
+подпись запроса; backend доверяет вердикту gateway.
 
 Gateway нужен публичный ключ сессии для проверки подписи, поэтому
 каждый аутентифицированный запрос разрешает устройство-сессию через
@@ -618,13 +624,18 @@ Wire-формат команд, приказов и отчётов — собс
 
 ### 6.2 Роль backend: pass-through с авторизацией
 
-Signed-gRPC-конвейер для in-game-трафика использует три message
+Подписанный конвейер аутентифицированного edge для in-game-трафика
-types на аутентифицированной поверхности — `user.games.command`,
+использует четыре message types на аутентифицированной поверхности —
-`user.games.order`, `user.games.report` — у каждого типизированный
+`user.games.command`, `user.games.order`, `user.games.order.get`,
-FlatBuffers-payload. Gateway транскодирует FB-запрос в JSON-форму,
+`user.games.report` — у каждого типизированный FlatBuffers-payload.
-которую ждёт backend, форвардит её REST'ом в соответствующий
+Gateway транскодирует FB-запрос в JSON-форму, которую ждёт backend,
+форвардит её REST'ом в соответствующий
 `/api/v1/user/games/{game_id}/*` endpoint, после чего транскодирует
 JSON-ответ обратно в FB перед подписью.
+`user.games.order.get` — read-back-компаньон для `user.games.order`:
+клиент использует его, чтобы восстановить локальный черновик приказа
+после потери кэша (свежая установка, очищенное хранилище, новое
+устройство).
 
 Для каждого in-game-endpoint user-surface работает как
 авторизующий pass-through к engine-контейнеру. Backend:
@@ -643,17 +654,40 @@ Backend не парсит содержимое payload команд или пр
 FB-форму только чтобы транскодировать wire-формат; per-command-
 семантика живёт в движке.
 
-### 6.3 Окно хода
+### 6.3 Окно хода и auto-pause
 
 Запущенная игра постоянно чередуется между окном приёма команд
-и фазой генерации. Переход `running → generation_in_progress` —
+и фазой генерации, управляемой cron-выражением из
-cutoff: любая команда или приказ, пришедшие после cutoff,
+`runtime_records.turn_schedule`. Backend-планировщик
-отклоняются backend до форварда, потому что движок больше не
+(`backend/internal/runtime/scheduler.go`) оборачивает каждый
-принимает запись для закрывающегося хода. После окончания
+engine `/admin/turn` двумя `runtime_status`-флипами:
-генерации backend заново открывает окно для следующего хода.
+
+- Перед engine-вызовом: `running → generation_in_progress`.
+  User-games-handler'ы команд/приказов
+  (`backend/internal/server/handlers_user_games.go`) на каждом
+  запросе сверяются с per-game runtime-записью и отклоняют с
+  HTTP 409 + `code = turn_already_closed`, пока runtime в
+  `generation_in_progress`. Тело ошибки — стандартный
+  `httperr`-конверт: `{"error": {"code": "turn_already_closed",
+  "message": "..."}}`.
+- После успешного тика: `generation_in_progress → running`.
+  Окно приказов открывается на новый ход, следующий тик идёт
+  как обычно.
+- После провалившегося тика (`engine_unreachable` /
+  `generation_failed`): `lobby.OnRuntimeSnapshot` переводит игру
+  `running → paused` и публикует push-эвент `game.paused`
+  (см. §6.6). Order-handler'ы отклоняют запросы с HTTP 409 +
+  `code = game_paused`, пока админ не выполнит resume.
 
 `force-next-turn` (admin) планирует one-shot-доп-тик, который
-сдвигает следующий запланированный ход на один cron-шаг.
+сдвигает следующий запланированный ход на один cron-шаг; те же
+правила status-flip и отклонения применимы.
+
+Клиенты различают два варианта отказа по `code`:
+`turn_already_closed` — «дождись следующего `game.turn.ready` и
+отправь ещё раз», `game_paused` — «дождись resume администратором».
+Web-клиент реализует оба сценария согласно
+`ui/docs/sync-protocol.md`.
 
 ### 6.4 Отчёты
 
@@ -661,7 +695,79 @@ Per-turn-отчёты — read-only-вью, забираемые из движк
 Backend авторизует вызывающего и форвардит запрос; в этом пути
 нет ни кэширования, ни денормализации.
 
-### 6.5 Побочные эффекты
+Web-клиент рендерит отчёт как одну секцию на каждый FBS-массив
+(общие сведения, голоса, статус игроков, мои / чужие науки, мои /
+чужие классы кораблей, сражения, бомбардировки, приближающиеся
+группы, мои / чужие / необитаемые / неопознанные планеты, корабли в
+производстве, грузовые маршруты, мои флоты, мои / чужие /
+неопознанные группы кораблей). Пустые секции получают явную копию
+empty-state. Якоря секций отображены в sticky-TOC (на мобильном —
+`<select>`); позиция скролла сохраняется при переключении активного
+представления через SvelteKit `Snapshot` API.
+
+Секция бомбардировок — это плоская read-only-таблица: одна строка на
+событие, колонки `attacker`, `attack_power`, признак `wiped` и
+ресурсный снимок после удара. Секция сражений — список ссылок в
+Battle Viewer (см. [§6.5](#65-battle-viewer)).
+
+### 6.5 Battle viewer
+
+Battle Viewer — отдельное представление, заменяющее карту и
+показывающее одну битву. Входы:
+
+- Строка в секции «сражения» в Reports (ссылка с пиннингом
+  текущего хода через `?turn=`).
+- Battle-marker на карте (жёлтый крест через противоположные углы
+  квадрата, описанного вокруг круга планеты; толщина линий растёт
+  с длиной протокола).
+
+Сам Viewer — логически изолированный компонент, потребляющий
+`BattleReport` в форме `pkg/model/report/battle.go`. Страница-обёртка
+(`ui/frontend/src/lib/active-view/battle.svelte`) забирает отчёт
+через backend-маршрут
+`GET /api/v1/user/games/{game_id}/battles/{turn}/{battle_id}`,
+который проксирует ответ engine-эндпоинта
+`GET /api/v1/battle/:turn/:uuid`.
+
+Визуальная модель — радиальная: планета в центре, расы по внешней
+окружности на равных угловых интервалах, внутри расы — облако
+кружков по классам кораблей, выложенное Vogel-спиралью с биасом к
+планете (самая многочисленная группа по NumberLeft — ближе к
+планете, остальные раскручиваются спиралью позади). Tech-варианты
+одного `(race, className)` схлопываются в один визуальный нод
+`<className>:<numLeft>`; детали по тех-уровням остаются в Reports.
+Радиус кружка масштабируется по FullMass корабля (диапазон
+`[6, 24] px`, нормировка на самую тяжёлую группу в битве), так что
+тяжёлые корабли визуально доминируют. Наблюдатели (`inBattle:
+false`) не рисуются. Выбывшие расы убираются из сцены, оставшиеся
+перераспределяются на следующем кадре. Viewer закреплён по высоте
+viewport-а: сцена растягивается, лог скроллит внутри — никаких
+скроллов на уровне страницы.
+
+Каждый кадр — одна запись протокола; выстрел рисуется тонкой линией
+от атакующего к защитнику, красной при `destroyed`, зелёной иначе.
+Непрерывное воспроизведение: 1x / 2x / 4x (400 / 200 / 100 мс на
+кадр), плюс play/pause, шаг вперёд/назад, rewind. Текстовый протокол
+доступности под сценой дублирует те же события построчно.
+
+Бомбардировки и сражения умышленно не смешиваются: бомбардировки
+остаются статической таблицей в Reports; bombing-marker на карте —
+тонкая окружность вокруг планеты (жёлтая при damaged, красная при
+wiped), клик скроллит соответствующую строку в Reports.
+
+Текущая wire-форма отчёта несёт `battle: [{ id, planet, shots }]`
+на каждую битву, чтобы map-маркеры могли расположиться без
+дополнительного запроса полного `BattleReport`.
+
+Для DEV / e2e легаси-CLI
+(`tools/local-dev/legacy-report/cmd/legacy-report-to-json`) выдаёт
+envelope `{version: 1, report, battles}`, где `battles` несёт полные
+`BattleReport`-ы, распарсенные из `Battle at (#N)`-блоков. Synthetic-
+загрузчик в лобби разбирает envelope и регистрирует каждую битву
+через `registerSyntheticBattle`, так что Battle Viewer открывает
+любой UUID без сетевого запроса.
+
+### 6.6 Побочные эффекты
 
 Успешная генерация хода публикует runtime-snapshot в lobby-модуль,
 который обновляет денормализованное вью (текущий ход, runtime-
@@ -670,16 +776,34 @@ status, per-player-stats). Engine-отчёт "game finished" гонит
 ([Раздел 3.5](#35-отмена-и-завершение)) и триггерит Race Name
 Directory-промоушен ([Раздел 5](#5-реестр-названий-рас)).
 
-`game.*`-виды уведомлений (`game.started`, `game.turn.ready`,
+Из `game.*`-видов уведомлений подключены `game.turn.ready` и
-`game.generation.failed`, `game.finished`) зарезервированы в
+`game.paused`:
-документации, но **не имеют поставщика** в кодовой базе сегодня;
-notification-каталог явно их опускает
-(`backend/internal/notification/catalog.go`). Добавление поставщика
-аддитивно: зарегистрировать вид в каталоге, заполнить
-`MailTemplateID`, если нужен email-веер, и заставить нужный
-доменный модуль вызвать `notification.Submit`.
 
-### 6.6 Перекрёстные ссылки
+- `game.turn.ready` —
+  `lobby.Service.OnRuntimeSnapshot` (`backend/internal/lobby/runtime_hooks.go`)
+  выпускает один intent на каждое увеличение `current_turn`,
+  адресуя его всем активным membership-ам игры, с
+  idempotency-ключом `turn-ready:<game_id>:<turn>` и
+  JSON-payload-ом `{game_id, turn}`.
+- `game.paused` — тот же хук публикует один intent на каждое
+  выставление статуса `paused` по runtime-снапшоту
+  (`engine_unreachable` / `generation_failed`), адресуя его всем
+  активным membership-ам игры, с idempotency-ключом
+  `paused:<game_id>:<turn>` и JSON-payload-ом
+  `{game_id, turn, reason}`. `reason` несёт runtime-статус,
+  спровоцировавший переход, чтобы UI смог в будущем
+  дифференцировать копию.
+
+Оба вида направляются только в push-канал; email-фан-аут
+сознательно опущен, чтобы избежать спама на каждом ходе/паузе.
+
+Остальные `game.*`-виды (`game.started`, `game.generation.failed`,
+`game.finished`) и `mail.dead_lettered` зарезервированы без поставщика;
+добавление поставщика чисто аддитивное (зарегистрировать вид в
+каталоге, расширить `CHECK`-констрейнт миграции и вызвать
+`notification.Submit` из подходящего доменного модуля).
+
+### 6.7 Перекрёстные ссылки
 
 - Backend ↔ engine wire-контракт (`pkg/model/{order,report,rest}`):
   [ARCHITECTURE.md §9](ARCHITECTURE.md#9-backend--game-engine-communication).
@@ -697,9 +821,10 @@ notification-каталог явно их опускает
 
 ### 7.1 Состав
 
-В составе: gRPC-стрим, который клиент открывает к gateway,
+В составе: server-streaming-подписка, которую клиент открывает к
-bootstrap-событие, фрейминг форварднутых событий, control-канал
+gateway (Connect / gRPC / gRPC-Web фреймы все маршрутизируются на
-backend → gateway, который производит эти события.
+одну точку), bootstrap-событие, фрейминг форварднутых событий,
+control-канал backend → gateway, который производит эти события.
 
 Вне состава: каталог видов событий — см.
 [Раздел 8](#8-уведомления-и-почта) для notification-стороны и
@@ -1069,3 +1194,220 @@ dead-letters и malformed notification-намерения. Они также м
   [ARCHITECTURE.md §11](ARCHITECTURE.md#11-mail-outbox),
   [§12](ARCHITECTURE.md#12-notification-pipeline) и
   [Раздел 8](#8-уведомления-и-почта).
+
+---
+
+## 11. Дипломатическая почта
+
+Сценарий описывает обмен сообщениями между игроками одной партии и
+адресные / широковещательные уведомления от администрации и
+владельца партии. Подсистема концептуально часть лобби (сообщения
+переживают рестарты движка), но видна только внутри игрового UI;
+в лобби виден лишь счётчик непрочитанного.
+
+### 11.1 Состав
+
+В составе: отправка персональной почты между активными участниками
+одной партии; ответы на персональную почту; чтение, отметка
+«прочитано» и soft-удаление своей входящей почты; адресные и
+широковещательные уведомления от админов и владельцев; платный
+broadcast от игроков; мультигеймовая admin-рассылка; ручная
+массовая чистка почты завершённых партий; авто-перевод тела
+сообщения на `preferred_language` получателя с кэшированием.
+
+Вне состава: чат вне партии, групповые чаты с участниками разных
+партий, вложения, редактирование / отзыв сообщения,
+end-to-end-шифрование.
+
+### 11.2 Модель сообщения
+
+Каждая отправка порождает ровно одну строку в `diplomail_messages`
+плюс по одной строке на получателя в `diplomail_recipients`.
+Broadcast на N получателей — одно сообщение и N recipient-строк;
+строка перевода, если материализована, общая для всех получателей
+с одинаковым целевым языком.
+
+`diplomail_messages.kind` — закрытое множество
+`{personal, admin}`. Персональные сообщения допускают ответ
+(получатель отправляет новое персональное сообщение);
+admin-сообщения не предполагают ответа — это уведомления о смене
+состояния или операторском действии. `sender_kind` — это
+`{player, admin, system}` и определяет роль отправителя: игрок-
+владелец партии (admin-уведомление от owner), site-администратор
+(admin-уведомление от оператора) или собственно автомат лобби
+(`game.paused`, `game.cancelled`, `membership.removed`,
+`membership.blocked`).
+
+`broadcast_scope` фиксирует тип отправки: одному получателю
+(`single`), рассылка по одной партии (`game_broadcast`) или
+admin-рассылка по нескольким партиям (`multi_game_broadcast`).
+Получатели multi_game-рассылки видят отдельную, независимо
+удаляемую запись inbox в каждой адресованной партии.
+
+Снимки сохраняются прямо в строках сообщения и получателя:
+`game_name`, `sender_username`, `sender_ip` и на стороне
+получателя — `recipient_user_name`, `recipient_race_name` и
+`recipient_preferred_language`. Они переживают переименование
+партии, отзыв членства, soft-delete аккаунта и итоговый
+bulk-purge — admin observability отрисовывается корректно даже
+после исчезновения «живых» строк.
+
+Тела и subject — plain UTF-8 текст. Сервер не парсит, не санитайзит
+и не экранирует HTML; клиент рендерит тело через `textContent`.
+Максимум размера тела — `BACKEND_DIPLOMAIL_MAX_BODY_BYTES`
+(по умолчанию `4096`); максимум для subject —
+`BACKEND_DIPLOMAIL_MAX_SUBJECT_BYTES` (по умолчанию `256`).
+
+### 11.3 Отправка почты
+
+Персональная отправка требует активного членства в партии и от
+отправителя, и от получателя. Игроки free-tier отправляют одно
+персональное сообщение за запрос. Игрокам платных тиров доступен
+и игровой broadcast — одна отправка на всех остальных активных
+участников партии; ответы возвращаются автору broadcast.
+
+Владельцы (приватных партий) и site-администраторы отправляют
+admin-уведомления. Endpoint владельца находится на user-поверхности
+(аутентификация по `X-User-ID`, проверка владельца в обработчике);
+endpoint администратора — на admin-поверхности (HTTP Basic). Оба
+принимают `target=user` (один получатель) или `target=all`
+(broadcast в одной партии). Site-администратору доступен
+дополнительный multi-game endpoint, принимающий
+`scope=selected` со списком game_id или `scope=all_running` —
+перебор всех партий в нетерминальных состояниях.
+
+Состав получателей broadcast параметризуется полем `recipients`:
+`active` (по умолчанию), `active_and_removed` или `all_members`
+(включает блокированных, для аудит-уведомлений). Собственная
+recipient-строка автора broadcast не создаётся.
+
+Player-broadcast от free-tier пользователя отклоняется кодом
+`403 forbidden`.
+
+### 11.4 Получение почты
+
+Получатель видит сообщение в своём inbox только после того, как
+асинхронный worker перевода обработал его (см.
+[§11.6](#116-перевод)). До этого строка невидима: не выводится в
+inbox-листинге, не учитывается в badge непрочитанного, push-событие
+не доставляется. Это исключает ситуацию «строка появилась, перевод
+не подъехал, badge мигает».
+
+Badge непрочитанного в лобби агрегируется по партиям. Endpoint
+`/api/v1/user/lobby/mail/unread-counts` возвращает по одной записи
+на каждую партию с ненулевым unread плюс общий total; UI лобби
+отображает общий badge и плитки по партиям, не раскрывая самих
+сообщений.
+
+Mark-read идемпотентен. Soft-удаление требует, чтобы сообщение уже
+было помечено прочитанным — клиент не может стереть неоткрытое
+сообщение. Soft-удаление действует только для одного получателя:
+строка самого сообщения переживает удаление вплоть до admin
+bulk-purge всей почты соответствующей партии.
+
+Ответ message-detail содержит и оригинальное тело, и (если есть
+кэш) перевод; UI по умолчанию показывает перевод и предлагает
+переключение «показать оригинал».
+
+### 11.5 Хуки жизненного цикла
+
+Три транзитных перехода в лобби порождают system mail в inbox
+затронутых игроков:
+
+- **Пауза / отмена игры.** Когда автомат партии проходит через
+  `paused` или `cancelled`, лобби эмитит system-сообщение всем
+  активным членам. Текст рендерится сервером по шаблону, чтобы
+  игрок, открывший inbox позже, нашёл объяснение даже без
+  одновременной push-сессии.
+- **Удаление / блокировка членства.** Сам-выход, удаление
+  владельцем и admin-бан порождают system-сообщение только для
+  затронутого игрока. Это письмо переживает переход членства в
+  `removed` / `blocked` — игрок сохраняет к нему read-доступ
+  навсегда (правило soft-доступа).
+
+Будущее удаление по неактивности должно вызывать тот же publisher,
+чтобы объяснение дошло до затронутого игрока; README пакета
+прибивает этот контракт для следующего реализатора.
+
+### 11.6 Перевод
+
+`diplomail_messages.body_lang` заполняется на стороне сервера в
+момент отправки внутрипроцессным детектором языка, работающим
+только по телу. Subject наследует язык тела для ключа кэша
+перевода. Когда детектор не может уверенно классифицировать тело
+(слишком короткое, пустое, смешанные скрипты), значение —
+плейсхолдер BCP 47 `und` ("неопределённый"), и pipeline перевода
+обходится стороной — получатели видят оригинал.
+
+Перевод выполняется асинхронно. Каждая recipient-строка содержит
+снимок `preferred_language` получателя плюс метку `available_at`.
+Получатель, чей язык совпадает с детектированным `body_lang` (или
+чей preferred_language пуст / язык тела — `und`), получает
+`available_at = now()` сразу при вставке, и push-событие
+отправляется в момент `POST`. Получатель с отличающимся языком
+вставляется с `available_at IS NULL` и ждёт worker.
+
+Worker (`internal/diplomail.Worker`) тикает каждые
+`BACKEND_DIPLOMAIL_WORKER_INTERVAL` (по умолчанию `2s`) и
+обрабатывает по одной паре `(message_id, target_lang)` за тик. Он
+сначала смотрит в кэш переводов; на miss дёргает настроенный
+`Translator`. Дефолт production-сборки — LibreTranslate HTTP
+клиент; пустой `BACKEND_DIPLOMAIL_TRANSLATOR_URL` оставляет
+noop-translator, который доставляет сообщение в оригинале.
+
+Исходы перевода:
+
+- **Успех.** Строка в `diplomail_translations` создаётся (или
+  переиспользуется, если параллельная попытка успела раньше),
+  все pending-получатели пары переключаются на
+  `available_at = now()`, и по каждому отправляется push.
+- **Неподдерживаемая пара языков** (HTTP 400 от LibreTranslate).
+  Строка перевода не сохраняется; получатели доставляются с
+  оригинальным телом. Последующие чтения возвращают оригинал.
+- **Транзитный сбой** (timeout, 5xx, network error). Счётчик
+  попыток увеличивается, следующая попытка планируется по
+  экспоненциальному backoff `1s → 2s → 4s → 8s → 16s`
+  (с потолком 60s). После
+  `BACKEND_DIPLOMAIL_TRANSLATOR_MAX_ATTEMPTS` (по умолчанию `5`)
+  worker fallback'ит на оригинальное тело. Длительный отказ
+  переводчика тормозит доставку максимум на ~30 секунд на пару
+  до того, как получатель увидит оригинал.
+
+Кэш переводов общий: broadcast на N получателей с одинаковым
+preferred_language порождает одну строку кэша и один вызов
+переводчика, не N.
+
+### 11.7 Хранение и purge
+
+Сообщения живут в `diplomail_messages`; per-recipient state — в
+`diplomail_recipients` с FK-каскадом на сообщение; переводы — в
+`diplomail_translations` тоже с каскадом. IP-адрес отправителя
+снимается из `X-Forwarded-For` (форвардит gateway) и хранится в
+сообщении для сохранения доказательств.
+
+Автоматического retention нет. Admin bulk-purge endpoint удаляет
+все сообщения, чья партия завершилась более `older_than_years`
+лет назад (минимум `1`); каскад удаляет recipient- и
+translation-строки той же транзакцией.
+
+### 11.8 Видимость для оператора
+
+Admin-поверхность экспонирует постраничный листинг всех сообщений
+(`/api/v1/admin/mail/messages`) с фильтрами по `game_id`, `kind`
+и `sender_kind`. Bulk-purge endpoint
+(`/api/v1/admin/mail/cleanup`) принимает порог
+`older_than_years`. Per-game admin-отправки и multi-game
+broadcast'ы доступны через `/api/v1/admin/games/{game_id}/mail`
+и `/api/v1/admin/mail/broadcast`.
+
+### 11.9 Перекрёстные ссылки
+
+- Обзор пакета и карта стадий:
+  [`backend/internal/diplomail/README.md`](../backend/internal/diplomail/README.md).
+- Рецепт развёртывания LibreTranslate для локальной разработки:
+  [`backend/docs/diplomail-translator-setup.md`](../backend/docs/diplomail-translator-setup.md).
+- Детали хранения:
+  [ARCHITECTURE.md §12.1](ARCHITECTURE.md#121-diplomatic-mail-subsystem).
+- Push-транспорт для событий доставки: [Раздел 7](#7-канал-push).
+- Notification-каталог: kind `diplomail.message.received`:
+  [`backend/README.md` §10](../backend/README.md#10-notification-catalog).

game/.gitignore

@@ -0,0 +1 @@
+artifacts/

game/README.md

@@ -49,6 +49,7 @@ described below. Endpoints split into two route classes:
 | Admin (GM-only) | `POST /api/v1/admin/race/banish` | `Game Master` | Deactivate a race after a permanent platform removal. |
 | Player | `PUT /api/v1/command` | `Game Master` (forwarded from `Edge Gateway`) | Execute a batch of player commands. |
 | Player | `PUT /api/v1/order` | `Game Master` | Validate and store a batch of player orders. |
+| Player | `GET /api/v1/order` | `Game Master` | Fetch the previously stored player order for a turn. |
 | Player | `GET /api/v1/report` | `Game Master` | Fetch the per-player turn report. |
 | Probe | `GET /healthz` | `Runtime Manager` | Technical liveness probe. |
 

game/internal/controller/battle_test.go

@@ -8,6 +8,7 @@ import (
 	"galaxy/calc"
 	"galaxy/game/internal/controller"
 	"galaxy/game/internal/model/game"
+	"galaxy/model/report"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -184,3 +185,89 @@ func TestProduceBattles(t *testing.T) {
 		assert.Zero(t, c.ShipGroup(3).Number)
 	}
 }
+
+// TestTransformBattleAggregatesSameShipClass guards against the
+// engine-side variant of the duplicate-class bug. Several ShipGroups
+// of the same ShipClass.ID can take part in the same battle (arrivals
+// from different planets, tech splits, etc.); they must collapse into
+// a single BattleReportGroup with summed Number and NumberLeft. The
+// pre-fix engine cached the first group's index and silently dropped
+// every subsequent group's initial / survivor counts, which manifested
+// downstream as more Destroyed shots in the protocol than the
+// recorded initial roster could account for.
+func TestTransformBattleAggregatesSameShipClass(t *testing.T) {
+	c, g := newCache()
+
+	assert.NoError(t, g.RaceRelation(Race_0.Name, Race_1.Name, game.RelationWar.String()))
+	assert.NoError(t, g.RaceRelation(Race_1.Name, Race_0.Name, game.RelationWar.String()))
+
+	// Two Race_0 groups of the SAME ship class (Race_0_Gunship) plus
+	// one Race_1 group of Race_1_Gunship — all parked on Planet_0
+	// (owned by Race_0; the Race_1 group lands there via the Unsafe
+	// helper that bypasses the ownership check). Group indices land
+	// at 0, 1, 2 in creation order.
+	assert.NoError(t, c.CreateShips(Race_0_idx, Race_0_Gunship, R0_Planet_0_num, 10))
+	assert.NoError(t, c.CreateShips(Race_0_idx, Race_0_Gunship, R0_Planet_0_num, 10))
+	c.CreateShipsUnsafe_T(Race_1_idx, c.MustShipClass(Race_1_idx, Race_1_Gunship).ID, R0_Planet_0_num, 5)
+
+	// Simulate post-battle survivor counts: Group 0 ended the battle
+	// with 8 ships, Group 1 with 6. The aggregated BattleReportGroup
+	// must report NumberLeft = 8 + 6 = 14 (not just the last cached
+	// group's 6 — that's the regression).
+	c.ShipGroup(0).Number = 8
+	c.ShipGroup(1).Number = 6
+
+	b := &controller.Battle{
+		Planet:         R0_Planet_0_num,
+		ObserverGroups: map[int]bool{0: true, 1: true, 2: true},
+		InitialNumbers: map[int]uint{0: 10, 1: 10, 2: 5},
+		// Protocol must reference every in-battle group at least once
+		// (otherwise TransformBattle won't register it through the
+		// `ship()` path). Two shots from Race_1 against each Race_0
+		// group hits both groupIds.
+		Protocol: []controller.BattleAction{
+			{Attacker: 2, Defender: 0, Destroyed: true},
+			{Attacker: 2, Defender: 1, Destroyed: true},
+		},
+	}
+
+	r := controller.TransformBattle(c, b)
+
+	// Two BattleReportGroup entries total: one merged Race_0_Gunship
+	// (groups 0 + 1) and one Race_1_Gunship. NOT three.
+	if got, want := len(r.Ships), 2; got != want {
+		t.Fatalf("len(r.Ships) = %d, want %d (duplicate ShipClass.ID must merge)", got, want)
+	}
+
+	var gunship0, gunship1 *report.BattleReportGroup
+	for i := range r.Ships {
+		grp := r.Ships[i]
+		switch grp.Race {
+		case Race_0.Name:
+			gunship0 = &grp
+		case Race_1.Name:
+			gunship1 = &grp
+		}
+	}
+	if gunship0 == nil || gunship1 == nil {
+		t.Fatalf("missing race entry: race0=%v race1=%v", gunship0, gunship1)
+	}
+
+	if gunship0.ClassName != Race_0_Gunship {
+		t.Errorf("race0.ClassName = %q, want %q", gunship0.ClassName, Race_0_Gunship)
+	}
+	if gunship0.Number != 20 {
+		t.Errorf("race0.Number = %d, want 20 (10+10)", gunship0.Number)
+	}
+	if gunship0.NumberLeft != 14 {
+		t.Errorf("race0.NumberLeft = %d, want 14 (8+6)", gunship0.NumberLeft)
+	}
+	if !gunship0.InBattle {
+		t.Errorf("race0.InBattle = false, want true (both source groups were in-battle)")
+	}
+
+	if gunship1.Number != 5 || gunship1.NumberLeft != 5 {
+		t.Errorf("race1 = (Number=%d, NumberLeft=%d), want (5, 5)",
+			gunship1.Number, gunship1.NumberLeft)
+	}
+}

game/internal/controller/battle_transform.go

@@ -18,10 +18,35 @@ func TransformBattle(c *Cache, b *Battle) *report.BattleReport {
 
 	cacheShipClass := make(map[uuid.UUID]int)
 	cacheRaceName := make(map[uuid.UUID]int)
+	processedGroup := make(map[int]bool)
 
 	addShipGroup := func(groupId int, inBattle bool) int {
 		shipClass := c.ShipGroupShipClass(groupId)
 		sg := c.ShipGroup(groupId)
+		// Several ship-groups of the same race/class can take part
+		// in the same battle (different tech upgrades, arrivals from
+		// different planets, …). They share a single
+		// BattleReportGroup entry keyed by ShipClass.ID — when a
+		// later group lands on a cached class we add its Number and
+		// NumberLeft into the existing entry instead of dropping
+		// them, so the protocol's per-class destroy counts reconcile
+		// with the recorded totals. `processedGroup` guards against
+		// double-counting a single groupId across multiple shots in
+		// the protocol — `ship()` runs on every attacker and defender
+		// reference, the merge must happen once per groupId.
+		if existing, ok := cacheShipClass[shipClass.ID]; ok {
+			if !processedGroup[groupId] {
+				bg := r.Ships[existing]
+				bg.Number += b.InitialNumbers[groupId]
+				bg.NumberLeft += sg.Number
+				if inBattle {
+					bg.InBattle = true
+				}
+				r.Ships[existing] = bg
+				processedGroup[groupId] = true
+			}
+			return existing
+		}
 		itemNumber := len(r.Ships)
 		bg := &report.BattleReportGroup{
 			Race:         c.g.Race[c.RaceIndex(sg.OwnerID)].Name,
@@ -31,22 +56,19 @@ func TransformBattle(c *Cache, b *Battle) *report.BattleReport {
 			ClassName:    shipClass.Name,
 			LoadType:     sg.CargoString(),
 			LoadQuantity: report.F(sg.Load.F()),
+			Tech:         make(map[string]report.Float, len(sg.Tech)),
 		}
 		for t, v := range sg.Tech {
 			bg.Tech[t.String()] = report.F(v.F())
 		}
 		r.Ships[itemNumber] = *bg
 		cacheShipClass[shipClass.ID] = itemNumber
+		processedGroup[groupId] = true
 		return itemNumber
 	}
 
 	ship := func(groupId int) int {
-		shipClass := c.ShipGroupShipClass(groupId)
+		return addShipGroup(groupId, true)
-		if v, ok := cacheShipClass[shipClass.ID]; ok {
-			return v
-		} else {
-			return addShipGroup(groupId, true)
-		}
 	}
 
 	race := func(groupId int) int {

game/internal/controller/controller.go

@@ -2,6 +2,7 @@ package controller
 
 import (
 	"errors"
+	"time"
 
 	"galaxy/game/internal/model/game"
 
@@ -37,6 +38,10 @@ type Repo interface {
 	// SaveBattle stores a new battle protocol and battle meta data for turn t
 	SaveBattle(uint, *report.BattleReport, *game.BattleMeta) error
 
+	// LoadBattle reads battle's protocol for turn t and battle id.
+	// Returns false if battle with such id was never stored at turn t
+	LoadBattle(t uint, id uuid.UUID) (*report.BattleReport, bool, error)
+
 	// SaveBombing stores all prodused bombings for turn t
 	SaveBombings(uint, []*game.Bombing) error
 
@@ -47,10 +52,10 @@ type Repo interface {
 	LoadReport(uint, uuid.UUID) (*report.Report, error)
 
 	// SaveOrder stores order for given turn
-	SaveOrder(uint, uuid.UUID, *order.Order) error
+	SaveOrder(uint, uuid.UUID, *order.UserGamesOrder) error
 
 	// LoadOrder loads order for specific turn and player id
-	LoadOrder(uint, uuid.UUID) (*order.Order, bool, error)
+	LoadOrder(uint, uuid.UUID) (*order.UserGamesOrder, bool, error)
 }
 
 type Ctrl interface {
@@ -126,14 +131,30 @@ func ExecuteCommand(configure func(*Param), consumer func(c Ctrl) error) (err er
 	return ec.executeCommand(func(c *Controller) error { return consumer(c) })
 }
 
-func ValidateOrder(configure func(*Param), actor string, cmd ...order.DecodableCommand) (err error) {
+func ValidateOrder(configure func(*Param), actor string, cmd ...order.DecodableCommand) (*order.UserGamesOrder, error) {
 	ec, err := NewRepoController(configure)
 	if err != nil {
-		return err
+		return nil, err
 	}
 	return ec.validateOrder(actor, cmd...)
 }
 
+func FetchOrder(configure func(*Param), actor string, turn uint) (order *order.UserGamesOrder, ok bool, err error) {
+	ec, err := NewRepoController(configure)
+	if err != nil {
+		return nil, false, err
+	}
+	return ec.fetchOrder(actor, turn)
+}
+
+func FetchBattle(configure func(*Param), turn uint, ID uuid.UUID) (b *report.BattleReport, exists bool, err error) {
+	ec, err := NewRepoController(configure)
+	if err != nil {
+		return nil, false, err
+	}
+	return ec.fetchBattle(turn, ID)
+}
+
 func BanishRace(configure func(*Param), actor string) error {
 	ec, err := NewRepoController(configure)
 	if err != nil {
@@ -213,8 +234,8 @@ func (ec *RepoController) NewGameController(g *game.Game) *Controller {
 	}
 }
 
-func (ec *RepoController) validateOrder(actor string, cmd ...order.DecodableCommand) (err error) {
+func (ec *RepoController) validateOrder(actor string, cmd ...order.DecodableCommand) (o *order.UserGamesOrder, err error) {
-	return ec.executeSafe(func(t uint, c *Controller) error {
+	err = ec.executeSafe(func(t uint, c *Controller) error {
 		id, err := c.RaceID(actor)
 		if err != nil {
 			return err
@@ -223,10 +244,41 @@ func (ec *RepoController) validateOrder(actor string, cmd ...order.DecodableComm
 		if err != nil {
 			return err
 		}
-		o := &order.Order{Commands: make([]order.DecodableCommand, len(cmd))}
+		o = &order.UserGamesOrder{
+			GameID:    c.Cache.g.ID,
+			UpdatedAt: time.Now().UTC().UnixMilli(),
+			Commands:  make([]order.DecodableCommand, len(cmd)),
+		}
 		copy(o.Commands, cmd)
 		return ec.Repo.SaveOrder(t, id, o)
 	})
+	if err != nil {
+		return nil, err
+	}
+	return
+}
+
+func (ec *RepoController) fetchOrder(actor string, turn uint) (order *order.UserGamesOrder, ok bool, err error) {
+	err = ec.executeSafe(func(t uint, c *Controller) error {
+		id, err := c.RaceID(actor)
+		if err != nil {
+			return err
+		}
+		order, ok, err = ec.Repo.LoadOrder(turn, id)
+		return err
+	})
+	if err != nil {
+		return
+	}
+	return
+}
+
+func (ec *RepoController) fetchBattle(turn uint, ID uuid.UUID) (order *report.BattleReport, exists bool, err error) {
+	err = ec.executeSafe(func(t uint, c *Controller) error {
+		order, exists, err = ec.Repo.LoadBattle(turn, ID)
+		return err
+	})
+	return
 }
 
 func (ec *RepoController) loadReport(actor string, turn uint) (r *report.Report, err error) {

game/internal/controller/fleet_send.go

@@ -1,8 +1,7 @@
 package controller
 
 import (
-	"galaxy/util"
+	"galaxy/calc"
-
 	e "galaxy/error"
 
 	"galaxy/game/internal/model/game"
@@ -25,7 +24,7 @@ func (c *Cache) FleetSend(ri, fi int, planetNumber uint) error {
 	if !ok {
 		return e.NewEntityNotExistsError("destination planet #%d", planetNumber)
 	}
-	rangeToDestination := util.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
+	rangeToDestination := calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
 	if rangeToDestination > c.g.Race[ri].FlightDistance() {
 		return e.NewSendUnreachableDestinationError("range=%.03f", rangeToDestination)
 	}

game/internal/controller/order.go

@@ -114,6 +114,7 @@ func (c *Controller) applyCommand(actor string, cmd order.DecodableCommand) (err
 
 func (c *Controller) applyOrders(t uint) error {
 	raceOrder := make(map[int][]order.DecodableCommand)
+	raceOrderUpdated := make(map[int]int64)
 	commandRace := make(map[string]string)
 	challenge := make(map[string]*order.CommandShipGroupUnload)
 	cmdApplied := make(map[string]bool)
@@ -127,6 +128,7 @@ func (c *Controller) applyOrders(t uint) error {
 			continue
 		}
 		raceOrder[ri] = o.Commands
+		raceOrderUpdated[ri] = o.UpdatedAt
 		for i := range o.Commands {
 			commandRace[o.Commands[i].CommandID()] = c.Cache.g.Race[ri].Name
 			if v, ok := order.AsCommand[*order.CommandShipGroupUnload](o.Commands[i]); ok {
@@ -156,10 +158,12 @@ func (c *Controller) applyOrders(t uint) error {
 			// any command might fail due to challenged planets colonization
 			_ = c.applyCommand(commandRace[cmd.CommandID()], cmd)
 		}
-	}
+		// re-save order to persist possible changed commands result outcome
-
+		if err := c.Repo.SaveOrder(t, c.Cache.g.Race[ri].ID, &order.UserGamesOrder{
-	for ri := range c.Cache.listRaceActingIdx() {
+			GameID:    c.Cache.g.ID,
-		if err := c.Repo.SaveOrder(t, c.Cache.g.Race[ri].ID, &order.Order{Commands: raceOrder[ri]}); err != nil {
+			UpdatedAt: raceOrderUpdated[ri],
+			Commands:  raceOrder[ri],
+		}); err != nil {
 			return err
 		}
 	}

game/internal/controller/planet.go

@@ -267,21 +267,20 @@ func (c *Cache) putMaterial(pn uint, v float64) {
 	c.MustPlanet(pn).Mat(v)
 }
 
+// ProduceShip returns number of ships with shipMass planet p can produce in one turn
 func ProduceShip(p *game.Planet, productionAvailable, shipMass float64) uint {
 	if productionAvailable <= 0 {
 		return 0
 	}
 	ships := uint(0)
 	pa := productionAvailable
-	PRODcost := calc.ShipProductionCost(shipMass)
+	var MATneed, totalCost float64
-	var MATneed, MATfarm, totalCost float64
 	for {
 		MATneed = shipMass - float64(p.Material)
 		if MATneed < 0 {
 			MATneed = 0
 		}
-		MATfarm = MATneed / float64(p.Resources)
+		totalCost = calc.ShipBuildCost(shipMass, float64(p.Material), float64(p.Resources))
-		totalCost = PRODcost + MATfarm
 		if pa < totalCost {
 			progress := pa / totalCost
 			pval := game.F(progress)

game/internal/controller/report.go

@@ -9,8 +9,6 @@ import (
 	"galaxy/calc"
 	mr "galaxy/model/report"
 
-	"galaxy/util"
-
 	"galaxy/game/internal/model/game"
 
 	"github.com/google/uuid"
@@ -39,7 +37,7 @@ func (c *Cache) InitReport(t uint) *mr.Report {
 		OtherScience:           make([]mr.OtherScience, 0, 10),
 		LocalShipClass:         make([]mr.ShipClass, 0, 20),
 		OtherShipClass:         make([]mr.OthersShipClass, 0, 50),
-		Battle:                 make([]uuid.UUID, 0, 10),
+		Battle:                 make([]mr.BattleSummary, 0, 10),
 		Bombing:                make([]*mr.Bombing, 0, 10),
 		IncomingGroup:          make([]mr.IncomingGroup, 0, 10),
 		OnPlanetGroupCache:     make(map[uint][]int),
@@ -94,7 +92,7 @@ func (c *Cache) InitReport(t uint) *mr.Report {
 			}
 			for pi := range c.g.Map.Planet {
 				p2 := &c.g.Map.Planet[pi]
-				distance := util.ShortDistance(c.g.Map.Width, c.g.Map.Height, sg.StateInSpace.X.F(), sg.StateInSpace.Y.F(), p2.X.F(), p2.Y.F())
+				distance := calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, sg.StateInSpace.X.F(), sg.StateInSpace.Y.F(), p2.X.F(), p2.Y.F())
 				report.InSpaceGroupRangeCache[sgi][p2.Number] = distance
 			}
 		} else {
@@ -344,7 +342,11 @@ func (c *Cache) ReportBattle(ri int, rep *mr.Report, br []*mr.BattleReport) {
 		}
 
 		sliceIndexValidate(&rep.Battle, i)
-		rep.Battle[i] = br[bi].ID
+		rep.Battle[i] = mr.BattleSummary{
+			ID:     br[bi].ID,
+			Planet: br[bi].Planet,
+			Shots:  uint(len(br[bi].Protocol)),
+		}
 		i++
 	}
 }
@@ -396,7 +398,7 @@ func (c *Cache) ReportIncomingGroup(ri int, rep *mr.Report) {
 			continue
 		}
 
-		distance := util.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
+		distance := calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
 		var speed, mass float64
 		if sg.FleetID != nil {
 			speed, mass = c.FleetSpeedAndMass(c.MustFleetIndex(*sg.FleetID))
@@ -597,7 +599,7 @@ func (c *Cache) ReportLocalFleet(ri int, rep *mr.Report) {
 		if inSpace, ok := fleetState.InSpace(); ok {
 			rep.LocalFleet[i].Origin = &inSpace.Origin
 			p2 := c.MustPlanet(rep.LocalFleet[i].Destination)
-			rangeToDestination := mr.F(util.ShortDistance(c.g.Map.Width, c.g.Map.Height, inSpace.X.F(), inSpace.Y.F(), p2.X.F(), p2.Y.F()))
+			rangeToDestination := mr.F(calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, inSpace.X.F(), inSpace.Y.F(), p2.X.F(), p2.Y.F()))
 			rep.LocalFleet[i].Range = &rangeToDestination
 		}
 		i++
@@ -726,7 +728,7 @@ func (c *Cache) otherGroup(v *mr.OtherGroup, sg *game.ShipGroup, st *game.ShipTy
 	if sg.State() == game.StateInSpace {
 		v.Origin = &sg.StateInSpace.Origin
 		p2 := c.MustPlanet(v.Destination)
-		rangeToDestination := mr.F(util.ShortDistance(c.g.Map.Width, c.g.Map.Height, sg.StateInSpace.X.F(), sg.StateInSpace.Y.F(), p2.X.F(), p2.Y.F()))
+		rangeToDestination := mr.F(calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, sg.StateInSpace.X.F(), sg.StateInSpace.Y.F(), p2.X.F(), p2.Y.F()))
 		v.Range = &rangeToDestination
 	}
 	v.Speed = mr.F(sg.Speed(st))

game/internal/controller/route.go

@@ -8,7 +8,7 @@ import (
 	"math/rand/v2"
 	"slices"
 
-	"galaxy/util"
+	"galaxy/calc"
 
 	e "galaxy/error"
 
@@ -28,7 +28,7 @@ func (c *Cache) PlanetRouteSet(ri int, rt game.RouteType, origin, destination ui
 	if !ok {
 		return e.NewEntityNotExistsError("destination planet #%d", destination)
 	}
-	rangeToDestination := util.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
+	rangeToDestination := calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
 	if rangeToDestination > c.g.Race[ri].FlightDistance() {
 		return e.NewSendUnreachableDestinationError("range=%.03f max=%.03f", rangeToDestination, c.g.Race[ri].FlightDistance())
 	}
@@ -194,7 +194,7 @@ func (c *Cache) RemoveUnreachableRoutes() {
 		ri := c.RaceIndex(*p1.Owner)
 		for rt, destination := range p1.Route {
 			p2 := c.MustPlanet(destination)
-			rangeToDestination := util.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
+			rangeToDestination := calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
 			if rangeToDestination > c.g.Race[ri].FlightDistance() {
 				delete(p1.Route, rt)
 			}

game/internal/controller/ship_group_send.go

@@ -1,8 +1,7 @@
 package controller
 
 import (
-	"galaxy/util"
+	"galaxy/calc"
-
 	e "galaxy/error"
 
 	"galaxy/game/internal/model/game"
@@ -47,7 +46,7 @@ func (c *Cache) shipGroupSend(ri int, groupID uuid.UUID, planetNumber uint) erro
 	if !ok {
 		return e.NewEntityNotExistsError("destination planet #%d", planetNumber)
 	}
-	rangeToDestination := util.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
+	rangeToDestination := calc.ShortDistance(c.g.Map.Width, c.g.Map.Height, p1.X.F(), p1.Y.F(), p2.X.F(), p2.Y.F())
 	if rangeToDestination > c.g.Race[ri].FlightDistance() {
 		return e.NewSendUnreachableDestinationError("range=%.03f", rangeToDestination)
 	}

game/internal/controller/ship_group_upgrade.go

@@ -5,6 +5,7 @@ import (
 	"slices"
 	"strings"
 
+	"galaxy/calc"
 	e "galaxy/error"
 
 	"galaxy/game/internal/model/game"
@@ -156,26 +157,19 @@ func (uc UpgradeCalc) UpgradeMaxShips(resources float64) uint {
 	return uint(math.Floor(resources / uc.UpgradeCost(1)))
 }
 
-func BlockUpgradeCost(blockMass, currentBlockTech, targetBlockTech float64) float64 {
-	if blockMass == 0 || targetBlockTech <= currentBlockTech {
-		return 0
-	}
-	return (1 - currentBlockTech/targetBlockTech) * 10 * blockMass
-}
-
 func GroupUpgradeCost(sg *game.ShipGroup, st game.ShipType, drive, weapons, shields, cargo float64) UpgradeCalc {
 	uc := &UpgradeCalc{Cost: make(map[game.Tech]float64)}
 	if drive > 0 {
-		uc.Cost[game.TechDrive] = BlockUpgradeCost(st.DriveBlockMass(), sg.TechLevel(game.TechDrive).F(), drive)
+		uc.Cost[game.TechDrive] = calc.BlockUpgradeCost(st.DriveBlockMass(), sg.TechLevel(game.TechDrive).F(), drive)
 	}
 	if weapons > 0 {
-		uc.Cost[game.TechWeapons] = BlockUpgradeCost(st.WeaponsBlockMass(), sg.TechLevel(game.TechWeapons).F(), weapons)
+		uc.Cost[game.TechWeapons] = calc.BlockUpgradeCost(st.WeaponsBlockMass(), sg.TechLevel(game.TechWeapons).F(), weapons)
 	}
 	if shields > 0 {
-		uc.Cost[game.TechShields] = BlockUpgradeCost(st.ShieldsBlockMass(), sg.TechLevel(game.TechShields).F(), shields)
+		uc.Cost[game.TechShields] = calc.BlockUpgradeCost(st.ShieldsBlockMass(), sg.TechLevel(game.TechShields).F(), shields)
 	}
 	if cargo > 0 {
-		uc.Cost[game.TechCargo] = BlockUpgradeCost(st.CargoBlockMass(), sg.TechLevel(game.TechCargo).F(), cargo)
+		uc.Cost[game.TechCargo] = calc.BlockUpgradeCost(st.CargoBlockMass(), sg.TechLevel(game.TechCargo).F(), cargo)
 	}
 	return *uc
 }
@@ -218,7 +212,7 @@ func UpgradeGroupPreference(sg game.ShipGroup, st game.ShipType, tech game.Tech,
 		ti = len(su.UpgradeTech) - 1
 	}
 	su.UpgradeTech[ti].Level = game.F(v)
-	su.UpgradeTech[ti].Cost = game.F(BlockUpgradeCost(st.BlockMass(tech), sg.TechLevel(tech).F(), v) * float64(sg.Number))
+	su.UpgradeTech[ti].Cost = game.F(calc.BlockUpgradeCost(st.BlockMass(tech), sg.TechLevel(tech).F(), v) * float64(sg.Number))
 
 	sg.StateUpgrade = &su
 	return sg

game/internal/controller/ship_group_upgrade_test.go

@@ -13,12 +13,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestBlockUpgradeCost(t *testing.T) {
-	assert.Equal(t, 00.0, controller.BlockUpgradeCost(1, 1.0, 1.0))
-	assert.Equal(t, 25.0, controller.BlockUpgradeCost(5, 1.0, 2.0))
-	assert.Equal(t, 50.0, controller.BlockUpgradeCost(10, 1.0, 2.0))
-}
-
 func TestGroupUpgradeCost(t *testing.T) {
 	sg := &g.ShipGroup{
 		Tech: map[g.Tech]g.Float{

game/internal/generator/map.go

@@ -4,8 +4,7 @@ import (
 	"fmt"
 	"math/rand"
 
-	"galaxy/util"
+	"galaxy/calc"
-
 	"galaxy/game/internal/generator/plotter"
 )
 
@@ -59,7 +58,7 @@ func (m Map) NewCoordinate(deadZoneRaduis float64) (Coordinate, error) {
 }
 
 func (m Map) ShortDistance(from, to Coordinate) float64 {
-	return util.ShortDistance(m.Width, m.Height, from.X, from.Y, to.X, to.Y)
+	return calc.ShortDistance(m.Width, m.Height, from.X, from.Y, to.X, to.Y)
 }
 
 // RandI returns a random float64 value between min and max

game/internal/model/game/race.go

@@ -1,6 +1,7 @@
 package game
 
 import (
+	"galaxy/calc"
 	"strings"
 
 	"github.com/google/uuid"
@@ -54,9 +55,9 @@ func (r Race) TechLevel(t Tech) float64 {
 }
 
 func (r Race) FlightDistance() float64 {
-	return r.TechLevel(TechDrive) * 40
+	return calc.FligthDistance(r.TechLevel(TechDrive))
 }
 
 func (r Race) VisibilityDistance() float64 {
-	return r.TechLevel(TechDrive) * 30
+	return calc.VisibilityDistance(r.TechLevel(TechDrive))
 }

game/internal/repo/game.go

@@ -12,8 +12,8 @@ package repo
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
+	"slices"
 
 	"galaxy/model/order"
 	"galaxy/model/report"
@@ -29,7 +29,9 @@ const (
 )
 
 type storedOrder struct {
-	Commands []json.RawMessage `json:"cmd"`
+	GameID    uuid.UUID         `json:"game_id"`
+	UpdatedAt int64             `json:"updatedAt"`
+	Commands  []json.RawMessage `json:"cmd"`
 }
 
 func (o storedOrder) MarshalBinary() (data []byte, err error) {
@@ -116,9 +118,25 @@ func loadMeta(s Storage) (*game.GameMeta, error) {
 	return result, nil
 }
 
-func saveMeta(s Storage, t uint, gm *game.GameMeta) error {
+func loadTurnMeta(s Storage, turn uint) (*game.GameMeta, error) {
+	var result *game.GameMeta = new(game.GameMeta)
+	path := fmt.Sprintf("%s/%s", TurnDir(turn), metaPath)
+	exist, err := s.Exists(path)
+	if err != nil {
+		return nil, NewStorageError(err)
+	}
+	if !exist {
+		return result, nil
+	}
+	if err := s.ReadSafe(path, result); err != nil {
+		return nil, NewStorageError(err)
+	}
+	return result, nil
+}
+
+func saveMeta(s Storage, turn uint, gm *game.GameMeta) error {
 	// save turn's meta
-	path := fmt.Sprintf("%s/%s", TurnDir(t), metaPath)
+	path := fmt.Sprintf("%s/%s", TurnDir(turn), metaPath)
 	if err := s.Write(path, gm); err != nil {
 		return NewStorageError(err)
 	}
@@ -130,27 +148,43 @@ func saveMeta(s Storage, t uint, gm *game.GameMeta) error {
 	return nil
 }
 
-func (r *repo) SaveBattle(t uint, b *report.BattleReport, m *game.BattleMeta) error {
+func (r *repo) LoadBattle(turn uint, id uuid.UUID) (*report.BattleReport, bool, error) {
+	meta, err := loadTurnMeta(r.s, turn)
+	if err != nil {
+		return nil, false, err
+	}
+	i := slices.IndexFunc(meta.Battles, func(m game.BattleMeta) bool { return m.BattleID == id })
+	if i < 0 {
+		return nil, false, nil
+	}
+	result, err := loadBattle(r.s, turn, meta.Battles[i].BattleID)
+	if err != nil {
+		return nil, false, err
+	}
+	return result, true, nil
+}
+
+func (r *repo) SaveBattle(turn uint, b *report.BattleReport, m *game.BattleMeta) error {
 	meta, err := loadMeta(r.s)
 	if err != nil {
 		return err
 	}
-	err = saveBattle(r.s, t, b)
+	err = saveBattle(r.s, turn, b)
 	if err != nil {
 		return err
 	}
 	meta.Battles = append(meta.Battles, *m)
-	return saveMeta(r.s, t, meta)
+	return saveMeta(r.s, turn, meta)
 }
 
-func saveBattle(s Storage, t uint, b *report.BattleReport) error {
+func saveBattle(s Storage, turn uint, b *report.BattleReport) error {
-	path := fmt.Sprintf("%s/battle/%s.json", TurnDir(t), b.ID.String())
+	path := fmt.Sprintf("%s/battle/%s.json", TurnDir(turn), b.ID.String())
 	exist, err := s.Exists(path)
 	if err != nil {
 		return NewStorageError(err)
 	}
 	if exist {
-		return NewStateError(fmt.Sprintf("battle %v for turn %d already has been saved", b.ID, t))
+		return NewStateError(fmt.Sprintf("battle %v for turn %d already has been saved", b.ID, turn))
 	}
 	if err := s.Write(path, b); err != nil {
 		return NewStorageError(err)
@@ -158,7 +192,23 @@ func saveBattle(s Storage, t uint, b *report.BattleReport) error {
 	return nil
 }
 
-func (r *repo) SaveBombings(t uint, b []*game.Bombing) error {
+func loadBattle(s Storage, turn uint, id uuid.UUID) (*report.BattleReport, error) {
+	path := fmt.Sprintf("%s/battle/%s.json", TurnDir(turn), id.String())
+	exist, err := s.Exists(path)
+	if err != nil {
+		return nil, NewStorageError(err)
+	}
+	if !exist {
+		return nil, NewStateError(fmt.Sprintf("battle %v for turn %d never was saved", id, turn))
+	}
+	result := new(report.BattleReport)
+	if err := s.ReadSafe(path, result); err != nil {
+		return nil, NewStorageError(err)
+	}
+	return result, nil
+}
+
+func (r *repo) SaveBombings(turn uint, b []*game.Bombing) error {
 	meta, err := loadMeta(r.s)
 	if err != nil {
 		return err
@@ -166,11 +216,11 @@ func (r *repo) SaveBombings(t uint, b []*game.Bombing) error {
 	for i := range b {
 		meta.Bombings = append(meta.Bombings, *b[i])
 	}
-	return saveMeta(r.s, t, meta)
+	return saveMeta(r.s, turn, meta)
 }
 
-func (r *repo) SaveReport(t uint, rep *report.Report) error {
+func (r *repo) SaveReport(turn uint, rep *report.Report) error {
-	return saveReport(r.s, t, rep)
+	return saveReport(r.s, turn, rep)
 }
 
 func saveReport(s Storage, t uint, v *report.Report) error {
@@ -181,12 +231,12 @@ func saveReport(s Storage, t uint, v *report.Report) error {
 	return nil
 }
 
-func (r *repo) LoadReport(t uint, id uuid.UUID) (*report.Report, error) {
+func (r *repo) LoadReport(turn uint, id uuid.UUID) (*report.Report, error) {
-	return loadReport(r.s, t, id)
+	return loadReport(r.s, turn, id)
 }
 
-func loadReport(s Storage, t uint, id uuid.UUID) (*report.Report, error) {
+func loadReport(s Storage, turn uint, id uuid.UUID) (*report.Report, error) {
-	path := ReportDir(t, id)
+	path := ReportDir(turn, id)
 	result := new(report.Report)
 	exist, err := s.Exists(path)
 	if err != nil {
@@ -201,11 +251,11 @@ func loadReport(s Storage, t uint, id uuid.UUID) (*report.Report, error) {
 	return result, nil
 }
 
-func (r *repo) SaveOrder(t uint, id uuid.UUID, o *order.Order) error {
+func (r *repo) SaveOrder(t uint, id uuid.UUID, o *order.UserGamesOrder) error {
 	return saveOrder(r.s, t, id, o)
 }
 
-func saveOrder(s Storage, t uint, id uuid.UUID, o *order.Order) error {
+func saveOrder(s Storage, t uint, id uuid.UUID, o *order.UserGamesOrder) error {
 	path := OrderDir(t, id)
 	if err := s.WriteSafe(path, o); err != nil {
 		return NewStorageError(err)
@@ -213,11 +263,11 @@ func saveOrder(s Storage, t uint, id uuid.UUID, o *order.Order) error {
 	return nil
 }
 
-func (r *repo) LoadOrder(t uint, id uuid.UUID) (*order.Order, bool, error) {
+func (r *repo) LoadOrder(t uint, id uuid.UUID) (*order.UserGamesOrder, bool, error) {
 	return loadOrder(r.s, t, id)
 }
 
-func loadOrder(s Storage, t uint, id uuid.UUID) (*order.Order, bool, error) {
+func loadOrder(s Storage, t uint, id uuid.UUID) (*order.UserGamesOrder, bool, error) {
 	path := OrderDir(t, id)
 
 	exist, err := s.Exists(path)
@@ -228,17 +278,22 @@ func loadOrder(s Storage, t uint, id uuid.UUID) (*order.Order, bool, error) {
 		return nil, false, nil
 	}
 
-	cmd := new(storedOrder)
+	stored := new(storedOrder)
-	if err := s.ReadSafe(path, cmd); err != nil {
+	if err := s.ReadSafe(path, stored); err != nil {
 		return nil, false, NewStorageError(err)
 	}
-	result := &order.Order{Commands: make([]order.DecodableCommand, len(cmd.Commands))}
+	// An empty stored batch is a valid state — the player either
-	if len(cmd.Commands) == 0 {
+	// cleared their draft or never added a command yet. We round-
-		return nil, false, errors.New("no commands were stored")
+	// trip it as `(*UserGamesOrder, true, nil)` with an empty
+	// `Commands` slice so callers can distinguish "no order yet"
+	// (ok=false) from "order exists but is empty" (ok=true).
+	result := &order.UserGamesOrder{
+		GameID:    stored.GameID,
+		UpdatedAt: stored.UpdatedAt,
+		Commands:  make([]order.DecodableCommand, len(stored.Commands)),
 	}
-
+	for i := range stored.Commands {
-	for i := range cmd.Commands {
+		command, err := ParseOrder(stored.Commands[i], nil)
-		command, err := ParseOrder(cmd.Commands[i], nil)
 		if err != nil {
 			return nil, false, err
 		}

game/internal/repo/repo_export_test.go

@@ -6,10 +6,10 @@ import (
 	"github.com/google/uuid"
 )
 
-func LoadOrder_T(s Storage, t uint, id uuid.UUID) (*order.Order, bool, error) {
+func LoadOrder_T(s Storage, t uint, id uuid.UUID) (*order.UserGamesOrder, bool, error) {
 	return loadOrder(s, t, id)
 }
 
-func SaveOrder_T(s Storage, t uint, id uuid.UUID, o *order.Order) error {
+func SaveOrder_T(s Storage, t uint, id uuid.UUID, o *order.UserGamesOrder) error {
 	return saveOrder(s, t, id, o)
 }

game/internal/repo/repo_test.go

@@ -3,6 +3,7 @@ package repo_test
 import (
 	"path/filepath"
 	"testing"
+	"time"
 
 	"galaxy/model/order"
 
@@ -18,7 +19,11 @@ func TestSaveOrder(t *testing.T) {
 	s, err := fs.NewFileStorage(root)
 	assert.NoError(t, err)
 	id := uuid.New()
-	o := &order.Order{
+	gameID := uuid.New()
+	now := time.Now().UTC().UnixMilli()
+	o := &order.UserGamesOrder{
+		GameID:    gameID,
+		UpdatedAt: now,
 		Commands: []order.DecodableCommand{
 			&order.CommandRaceVote{
 				CommandMeta: order.CommandMeta{
@@ -87,17 +92,63 @@ func TestSaveOrder(t *testing.T) {
 	LoadOrderTest(t, s, root, turn, id, o)
 }
 
-func LoadOrderTest(t *testing.T, s repo.Storage, root string, turn uint, id uuid.UUID, expected *order.Order) {
+func LoadOrderTest(t *testing.T, s repo.Storage, root string, turn uint, id uuid.UUID, expected *order.UserGamesOrder) {
 	o, ok, err := repo.LoadOrder_T(s, turn, id)
 	assert.NoError(t, err)
 	assert.True(t, ok)
 	assert.Len(t, o.Commands, 5)
+	assert.Equal(t, expected.GameID, o.GameID)
+	assert.Equal(t, expected.UpdatedAt, o.UpdatedAt)
 	assert.ElementsMatch(t, expected.Commands, o.Commands)
 
 	CommandResultTest(t, o)
 }
 
-func CommandResultTest(t *testing.T, o *order.Order) {
+func TestSaveOrderEmptyRoundTrip(t *testing.T) {
+	// An empty order is a legal player intent (the user removed
+	// every command from the draft). The repo round-trips it as an
+	// `(*UserGamesOrder, true, nil)` triple with `Commands` empty
+	// so the front-end can distinguish "no order yet" (ok=false)
+	// from "order exists but is empty" (ok=true).
+	root := t.ArtifactDir()
+	s, err := fs.NewFileStorage(root)
+	assert.NoError(t, err)
+	id := uuid.New()
+	gameID := uuid.New()
+	now := time.Now().UTC().UnixMilli()
+	o := &order.UserGamesOrder{
+		GameID:    gameID,
+		UpdatedAt: now,
+	}
+	var turn uint = 3
+
+	assert.NoError(t, repo.SaveOrder_T(s, turn, id, o))
+	assert.FileExists(t, filepath.Join(root, repo.OrderDir(turn, id)))
+
+	loaded, ok, err := repo.LoadOrder_T(s, turn, id)
+	assert.NoError(t, err)
+	assert.True(t, ok, "empty order must surface as ok=true so callers can tell it apart from a missing one")
+	assert.NotNil(t, loaded)
+	assert.Equal(t, gameID, loaded.GameID)
+	assert.Equal(t, now, loaded.UpdatedAt)
+	assert.Empty(t, loaded.Commands)
+}
+
+func TestLoadOrderMissing(t *testing.T) {
+	// A turn that has never had a PUT must come back as
+	// `(nil, false, nil)` — the engine's "no stored order" path.
+	root := t.ArtifactDir()
+	s, err := fs.NewFileStorage(root)
+	assert.NoError(t, err)
+	id := uuid.New()
+
+	loaded, ok, err := repo.LoadOrder_T(s, 7, id)
+	assert.NoError(t, err)
+	assert.False(t, ok)
+	assert.Nil(t, loaded)
+}
+
+func CommandResultTest(t *testing.T, o *order.UserGamesOrder) {
 	assert.NotEmpty(t, o.Commands)
 	for i := range o.Commands {
 		if v, ok := order.AsCommand[*order.CommandRaceVote](o.Commands[i]); ok {

game/internal/router/battle_test.go

@@ -0,0 +1,152 @@
+package router_test
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"galaxy/model/report"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetBattleValidation(t *testing.T) {
+	validUUID := uuid.New().String()
+
+	for _, tc := range []struct {
+		description  string
+		turn         string
+		battleID     string
+		expectStatus int
+	}{
+		{"Negative turn", "-1", validUUID, http.StatusBadRequest},
+		{"Non-numeric turn", "abc", validUUID, http.StatusBadRequest},
+		{"Invalid uuid", "0", invalidId, http.StatusBadRequest},
+	} {
+		t.Run(tc.description, func(t *testing.T) {
+			e := &dummyExecutor{}
+			r := setupRouterExecutor(e)
+
+			w := httptest.NewRecorder()
+			path := fmt.Sprintf("/api/v1/battle/%s/%s", tc.turn, tc.battleID)
+			req, _ := http.NewRequest(http.MethodGet, path, nil)
+			r.ServeHTTP(w, req)
+
+			assert.Equal(t, tc.expectStatus, w.Code, w.Body)
+			assert.Equal(t, uuid.Nil, e.FetchBattleID, "FetchBattle must not be called on validation error")
+		})
+	}
+}
+
+func TestGetBattleFound(t *testing.T) {
+	id := uuid.New()
+	raceA := uuid.New()
+	raceB := uuid.New()
+	stored := &report.BattleReport{
+		ID:         id,
+		Planet:     42,
+		PlanetName: "X-Prime",
+		Races: map[int]uuid.UUID{
+			0: raceA,
+			1: raceB,
+		},
+		Ships: map[int]report.BattleReportGroup{
+			10: {
+				Race:         "Alpha",
+				ClassName:    "Drone",
+				Tech:         map[string]report.Float{"WEAPONS": report.F(1)},
+				Number:       5,
+				NumberLeft:   3,
+				LoadType:     "EMP",
+				LoadQuantity: report.F(0),
+				InBattle:     true,
+			},
+			20: {
+				Race:         "Beta",
+				ClassName:    "Spy",
+				Tech:         map[string]report.Float{"SHIELDS": report.F(2)},
+				Number:       4,
+				NumberLeft:   0,
+				LoadType:     "EMP",
+				LoadQuantity: report.F(0),
+				InBattle:     true,
+			},
+		},
+		Protocol: []report.BattleActionReport{
+			{Attacker: 0, AttackerShipClass: 10, Defender: 1, DefenderShipClass: 20, Destroyed: true},
+		},
+	}
+	e := &dummyExecutor{
+		FetchBattleResult: stored,
+		FetchBattleOK:     true,
+	}
+	r := setupRouterExecutor(e)
+
+	w := httptest.NewRecorder()
+	path := fmt.Sprintf("/api/v1/battle/%d/%s", 7, id.String())
+	req, _ := http.NewRequest(http.MethodGet, path, nil)
+	r.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code, w.Body)
+	assert.Equal(t, uint(7), e.FetchBattleTurn)
+	assert.Equal(t, id, e.FetchBattleID)
+
+	var got report.BattleReport
+	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &got))
+	assert.Equal(t, stored.ID, got.ID)
+	assert.Equal(t, stored.Planet, got.Planet)
+	assert.Equal(t, stored.PlanetName, got.PlanetName)
+	assert.Equal(t, stored.Races, got.Races)
+	require.Len(t, got.Ships, len(stored.Ships))
+	assert.Equal(t, stored.Ships[10].ClassName, got.Ships[10].ClassName)
+	assert.Equal(t, stored.Ships[20].NumberLeft, got.Ships[20].NumberLeft)
+	require.Len(t, got.Protocol, 1)
+	assert.Equal(t, stored.Protocol[0], got.Protocol[0])
+}
+
+func TestGetBattleTurnZero(t *testing.T) {
+	id := uuid.New()
+	e := &dummyExecutor{
+		FetchBattleResult: &report.BattleReport{ID: id},
+		FetchBattleOK:     true,
+	}
+	r := setupRouterExecutor(e)
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, fmt.Sprintf("/api/v1/battle/0/%s", id.String()), nil)
+	r.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code, w.Body)
+	assert.Equal(t, uint(0), e.FetchBattleTurn)
+	assert.Equal(t, id, e.FetchBattleID)
+}
+
+func TestGetBattleNotFound(t *testing.T) {
+	id := uuid.New()
+	e := &dummyExecutor{FetchBattleOK: false}
+	r := setupRouterExecutor(e)
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, fmt.Sprintf("/api/v1/battle/3/%s", id.String()), nil)
+	r.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusNotFound, w.Code, w.Body)
+	assert.Equal(t, uint(3), e.FetchBattleTurn)
+	assert.Equal(t, id, e.FetchBattleID)
+}
+
+func TestGetBattleEngineError(t *testing.T) {
+	e := &dummyExecutor{FetchBattleErr: errors.New("engine boom")}
+	r := setupRouterExecutor(e)
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, fmt.Sprintf("/api/v1/battle/3/%s", uuid.NewString()), nil)
+	r.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusInternalServerError, w.Code, w.Body)
+}