Merge pull request 'Release: promote development → master (old Android WebView support + unsupported-engine telemetry)' (#178) from development into master

The index.html boot guard now fires a fire-and-forget beacon (POST /telemetry/unsupported)
when it turns a client away on the unsupported-engine screen, so the owner can see — on the
Users dashboard beside "app opens" — how many real clients hit it and on which engines.

- Client: navigator.sendBeacon (fetch fallback) with a localStorage dedup keyed by app version
  + reason + Chromium, so a user reopening the app is one report, not ten.
- Gateway: a new unauthenticated POST /telemetry/unsupported handler (the client never booted,
  so it carries no session), per-IP public-limited and body-capped, mirroring the export-download
  route. It folds the beacon into the OTel counter unsupported_engine_total {reason =
  no_bigint/no_proxy/boot_error/other, chromium}, with reason allow-listed and the Chromium major
  reduced to a bounded range (normalizeUnsupported) so a spoofed beacon cannot inflate the metric
  cardinality; the full user agent is logged, not labelled.
- Caddy: /telemetry/* added to the @gateway matcher (else it falls to the landing catch-all).
- Grafana: two panels on the Scrabble — Users dashboard (by reason, by Chromium major).
- Docs: ARCHITECTURE.md §11.

Tests: recordUnsupportedEngine (metric split), normalizeUnsupported (cardinality bounding), and
the handler route end to end (204 / 405 / counter). go build+vet+test and gofmt clean; ui
check/build/e2e green; the client beacon + dedup verified against a forced hard-gate (BigInt
removed) — one POST, deduped on reopen, correct reason/chromium/version labels.

.claude/skills/deploy-check/SKILL.md

@@ -0,0 +1,89 @@
+---
+name: deploy-check
+description: "Use before any deploy-touching change to this repo — phrases like '/deploy-check', 'is this prod-safe', 'before we deploy', 'deploy safety review', 'проверь перед деплоем', 'это безопасно для прода'. Runs a pre-deploy checklist of this project's hard-won runtime constraints against the current diff, so the crash classes that have bitten live environments get caught before shipping instead of after."
+---
+
+# Pre-deploy runtime-constraint check
+
+Triggered before shipping anything that touches the deploy contour (Dockerfiles,
+`deploy/`, Caddyfile, compose, migrations, boot guards, the Telegram side-service,
+edge config). The worst frictions in this repo were never logic bugs — they were
+**environment mismatches that crashed a live env and forced a redesign**. Run this
+list against the diff first; turn crash-and-redesign into a single pass.
+
+This checklist is a prompt, **not** the source of truth. The canonical detail
+lives in `deploy/README.md`, `docs/ARCHITECTURE.md`, `docs/EDGE_HTTP3.md`, and the
+agent memory files referenced below — read them when an item is in play, and add a
+new class here when a new incident teaches one.
+
+## How to run it
+
+1. `git diff <base>...HEAD --stat` to see what the change actually touches.
+2. For every risk class below that the diff touches, perform the **Check** and
+   report PASS / FAIL with the exact file:line to fix. Skip classes the diff does
+   not touch — say which you skipped and why.
+3. Remember: **deploy-job green ≠ healthy**. CI's deploy probe has historically
+   passed with a dead backend (it only checked static landing+gateway). Verify the
+   real feature live (`/readyz`, the actual flow) after deploy, not just the green.
+
+## Risk classes
+
+### 1. Container user — distroless nonroot UID 65532
+- **Bit us:** TLS keys `chmod 600` for the host owner crash-looped gateway + bot at
+  boot with "permission denied" — service images run UID 65532.
+- **Check:** any new/changed mounted secret, key, or config file must be readable by
+  UID 65532 (`0644`, not `0600`). Scan the diff for file modes, `chmod`, and new
+  volume mounts. (memory: `distroless-nonroot-mounted-secrets`)
+
+### 2. Caddy header pipeline ordering
+- **Bit us:** `header_up delete` after `set` nulled the value (the honeypot tag went
+  empty); it passed CI and only showed up live.
+- **Check:** in any Caddyfile change, verify the `set` / `delete` / `header_up`
+  ordering for every affected route, and test the tripwire/route on the live
+  contour, not just CI.
+
+### 3. Edge Alt-Svc / HTTP3
+- **Bit us:** edge advertised `Alt-Svc: h3` while UDP/443 was never exposed
+  (docker tcp-only + ufw tcp-only); clients cached it 30 days and stalled on dead
+  QUIC before falling back to h2 — Mini App "hangs on load".
+- **Check:** any edge/caddy change keeps `Alt-Svc: clear` (or only advertises h3 if
+  UDP/443 is genuinely exposed). (memory: `tg-app-load-stall-dead-http3-altsvc`,
+  `docs/EDGE_HTTP3.md`)
+
+### 4. Prod caddy config recreate
+- **Bit us:** prod rolling deploy did **not** recreate caddy on a config-only change
+  (pinned `caddy:2-alpine` + `admin off`), so a new Caddyfile deployed GREEN but
+  stayed inert until a manual `docker restart`.
+- **Check:** a config-only edge change must `--force-recreate` caddy in
+  `prod-deploy.sh` `roll()`; never trust deploy-green for edge config.
+  (memory: `prod-deploy-caddy-config-recreate`)
+
+### 5. DICT_VERSION / dictionary boot
+- **Bit us:** an early `DICT_VERSION` refuse-boot guard was wrong and crashed the
+  live env when bumped on a seeded volume; it had to be redesigned to "marker-wins".
+- **Check:** any change touching `DICT_VERSION`, dict load, or the boot guard must
+  keep marker-wins semantics and survive a seeded volume **and** an image rollback.
+  `DICT_VERSION` is a required build-arg (no default), single-sourced. A new dict
+  goes live via the admin console upload, not a redeploy. (memory:
+  `dict-version-deploy-verify`, `contour-schema-change-wipe`)
+
+### 6. Migrations — expand-contract + rollback safety
+- **Bit us / risk:** a non-backward-compatible migration breaks image rollback (DB
+  ahead of rolled-back code).
+- **Check:** migrations must be **expand-contract** (backward-compatible). A schema
+  change adds the maintenance window + a consistent `pg_dump` in prod-deploy. On the
+  **test contour**, a schema/wire-label change needs `DROP SCHEMA backend CASCADE` +
+  backend restart (new code vs old persisted DB), else the contour breaks. (memory:
+  `contour-schema-change-wipe`)
+
+### 7. Telegram permission model
+- **Bit us:** permissions are an **AND-intersection** — default-allow with explicit
+  denies, not default-deny; inverting it broke access.
+- **Check:** any change to the Telegram permission / relay logic preserves the
+  AND-intersection default-allow shape. (memory: `telegram-forum-relay-gotchas`)
+
+## Output
+
+A short PASS/FAIL table over the classes the diff touches, each FAIL with the exact
+file:line and the fix. If every touched class passes, say so plainly and name the
+post-deploy live check to run (not just "CI green").

.claude/vk-games-integration.md

@@ -0,0 +1,175 @@
+# VK Mini App / VK Games — integration reference
+
+Captured research + our implementation map, so a future session does not need to re-fetch
+the VK docs. Authoritative external source: <https://dev.vk.com/> (the `dev.vk.com` portal
+does not render via plain HTTP fetch; the facts below were cross-checked against the VKCOM
+reference repos cited at the end and verified against our own Go implementation).
+
+A VK **game** is technically a **VK Mini App**: an HTML5 SPA VK loads in an **iframe inside
+vk.com** (desktop + mobile web) and in a **WebView** inside the VK mobile apps (iOS/Android).
+We serve our existing SPA under a dedicated `/vk/` path, mirroring the Telegram `/telegram/`
+entry — the single-origin, path-routed model.
+
+## 1. Embedding model
+
+- VK loads the app at the **Web iframe URL** configured in the app settings (HTTPS + valid
+  cert required), appending the signed launch parameters as the **URL query string**.
+- An optional separate **Mobile iframe URL** is used by the VK mobile apps (we use the same).
+- No special `X-Frame-Options` / CSP `frame-ancestors` is required from us — VK frames the
+  configured origin. (Our edge sets **no** framing headers today, so VK works as-is; see the
+  clickjacking note in §Security.)
+- URL must match the settings exactly (scheme, host, no stray `www`/whitespace).
+
+## 2. Launch parameters (URL query)
+
+VK appends these to the iframe `src`. The `vk_*` set is what the signature covers.
+
+| Param | Meaning |
+| --- | --- |
+| `vk_user_id` | signed-in VK user numeric id — **the identity** |
+| `vk_app_id` | our registered app id |
+| `vk_is_app_user` | 0/1 — user authorized/installed the app |
+| `vk_are_notifications_enabled` | 0/1 |
+| `vk_language` | 2-letter UI language (`ru`, `en`, …) |
+| `vk_platform` | `mobile_iphone` \| `mobile_android` \| `mobile_web` \| `desktop_web` \| … |
+| `vk_ts` | unix seconds when VK generated the params |
+| `vk_ref` | where the app was opened from (`catalog`, `feed`, …) |
+| `vk_access_token_settings` | comma-separated granted scopes (often empty) |
+| `vk_group_id`, `vk_viewer_group_role`, `vk_is_favorite`, `vk_client` | optional/contextual |
+| `sign` | **the signature** (see §3) — NOT part of the signed set |
+
+Always present: `vk_user_id`, `vk_app_id`, `vk_platform`, `vk_ts`, `sign`.
+
+The user's **name is NOT in the launch params** (only `vk_user_id`). Read it client-side via
+`VKWebAppGetUserInfo` (see §4) — unsigned, so treat it as a cosmetic display seed only.
+
+## 3. Signature verification (`sign`)  — CONFIRMED base64url, not hex
+
+Algorithm (verified against our `gateway/internal/vkauth` + an independent Python reference):
+
+1. Collect the query params whose key starts with `vk_` (exclude `sign`).
+2. Sort by key (alphabetical).
+3. Serialize as a URL-encoded query string `k=v&k=v…` (Go `url.Values.Encode()` matches VK's
+   reference serialization for the constrained launch-param charset).
+4. `HMAC-SHA256(serialized, secret)` where `secret` = the app's **«Защищённый ключ»**
+   (protected / secure key, a.k.a. client_secret) from the app settings.
+5. **base64url, no padding** (`+`→`-`, `/`→`_`, strip `=`).
+6. Constant-time compare against `sign`.
+
+VK launch params have **no built-in expiry** (unlike Telegram's `auth_date`). We do NOT enforce
+freshness — the minted server session is the short-lived credential; a replay only
+re-authenticates the same `vk_user_id`.
+
+Verified against the official doc <https://dev.vk.com/ru/mini-apps/development/launch-params-sign>
+(prose + PHP example: base64url = `strtr('+/','-_')` + `rtrim('=')`) and reproduced identically by
+independent Node `crypto` + Python references. **Doc-example caveat**: that page shows secret
+`wvl68m4dR1UpLrVRli` → sign `exTIBP…`, but the secret is a **placeholder** — recomputing with it does
+NOT yield the shown sign (it was made with the real, unshown key). Don't chase the mismatch; our
+`vkauth.Verify` is correct (`gateway/internal/vkauth/vkauth_test.go` carries cross-checked vectors,
+incl. the `%2C` comma case for `vk_access_token_settings`).
+
+## 4. VK Bridge (client SDK)
+
+`@vkontakte/vk-bridge` (npm, v3.x; bundled — `default` export `bridge`). Methods we use / may use:
+
+- `VKWebAppInit` — **required**: tells VK the Mini App loaded (dismisses VK's loading cover).
+- `VKWebAppGetUserInfo` — `{ id, first_name, last_name, photo_200, … }`; no extra scope needed.
+- `VKWebAppGetLaunchParams` — parsed `vk_*` **without** `sign` (so NOT usable for our server
+  verification — read `window.location.search` instead, which carries `sign`).
+- `VKWebAppGetAuthToken` — OAuth access token for VK API calls (only if we ever call VK API).
+- `VKWebAppShare` — native share dialog (the friend-code invite uses it; `navigator.share` is absent
+  in the desktop VK iframe). **Used.**
+- `VKWebAppCopyText` — clipboard copy that works inside the VK iframe, where `navigator.clipboard` is
+  blocked. **Used** as the copy-code / copy-link path.
+- `VKWebAppUpdateConfig` (subscribe) — light/dark scheme; the app follows it while the theme pref is
+  "auto" (the VK webview's prefers-color-scheme does not track it). **Used.**
+- `VKWebAppSetViewSettings` / `VKWebAppSetSwipeSettings` — viewport / swipe-back (mobile); not used.
+- `VKWebAppUpdateInsets` (+ `VKWebAppUpdateConfig`) — device safe-area insets; the app **max'es** them
+  with CSS `env(safe-area-inset-*)` (viewport-fit=cover) so the bottom home bar is cleared. The bridge
+  value is needed on Android, where the VK webview exposes no `env()` inset. **Used.**
+
+The bridge talks to the embedding VK client over postMessage; it is NOT an external fetch, so
+it has no telegram.org-style load-hang risk. The SDK reads browser globals at import — we import
+it **lazily** so the pure URL helpers stay node-test-importable.
+
+**Deep links — NOT possible on VK (confirmed on the contour).** The VK iframe receives ONLY the signed
+`vk_*` launch params (+ `sign`); VK strips any custom data from the app link. The documented
+`vk.com/app<id>#<payload>` form is eaten by the vk.com SPA (which owns the URL hash), and a
+`vk.com/app<id>?hash=<payload>` query is dropped (the diagnostic showed `rawSearch` with only `vk_*`
+and an empty `hash`). So the friend-code invite link is just `vk.com/app<id>` (`vkShareLink`, app id
+from `vk_app_id`); the recipient enters the **copied code by hand** (`VKWebAppCopyText` works). The
+`vkStartParam` reader + the `bootVK` routing stay as a no-op today, ready if a post-moderation VK
+channel (e.g. an invite API) ever delivers a payload.
+
+## 5. Test mode (to verify before moderation)
+
+1. App already registered (we have the App ID).
+2. In the app settings (dev.vk.com / `vk.com/editapp?act=settings&app_id=<id>`):
+   - Category = **Игра** (Game).
+   - **Web iframe URL** = our public HTTPS `/vk/` (the test-contour origin for contour testing,
+     prod `https://erudit-game.ru/vk/` later). Mobile iframe URL = same.
+   - Copy the **«Защищённый ключ»** → set as `GATEWAY_VK_APP_SECRET` (Gitea `TEST_`/`PROD_` secret).
+   - Add own VK id to **testers**; open in test mode.
+3. Test mode = visible only to admins/testers, no payments processed.
+
+## 6. Auth / identity (our model)
+
+- `vk_user_id` (from verified params) → backend identity `kind='vk'`, `external_id=vk_user_id`,
+  auto-confirmed (a platform identity). First contact seeds language from `vk_language` and the
+  display name from the client-supplied `VKWebAppGetUserInfo` name (placeholder if empty).
+- No VK access token / VK API call needed for the launch+login MVP.
+
+## 7. Payments / monetization
+
+VK Pay / «голоса» (votes) are **optional**, not required to publish a free game. Not planned.
+
+## 8. ToS / moderation (pre-publish, analyzed — no blocker for a free «Эрудит»)
+
+- **Trademark**: "Scrabble" is trademarked. Our public brand is **«Эрудит»** (erudit-game.ru),
+  a generic Russian word-game name → fine. Ensure the VK-registered app name is «Эрудит»/word-game,
+  NOT "Scrabble". The repo name is internal and irrelevant to moderation.
+- **Pre-publish requirements**: public **Privacy Policy** + **ToS** URLs (disclose collected data:
+  `vk_user_id`, language; mention VK), **age rating** (likely 6+/12+), icon, description.
+- **Dictionary**: standard word lists; VK may expect offensive-word filtering — likely fine for a
+  dictionary game, flag if moderation asks.
+- **In-game chat (UGC)**: we already have a moderated chat + support relay → covered.
+- Moderation reviews after submission (commonly ~24–72h); rejects on violence/hate/sexual/illegal
+  content or IP infringement — none apply.
+
+## 9. Platforms
+
+Desktop web (iframe), mobile web (iframe), VK iOS app (WKWebView), VK Android app (WebView). Bridge
+methods behave per-platform; the app's own back chevron + app-shell document-pin cover navigation
+without VK-specific code. Theme/viewport fine-tuning is best verified live in the real VK client
+(not reproducible in Playwright — like the iOS gesture caveats).
+
+## 10. Our implementation map (what to touch for VK)
+
+- **Wire**: `pkg/fbs/scrabble.fbs` → `VKLoginRequest{ params, browser_tz, display_name }`
+  (regen: `make -C pkg fbs` + `pnpm -C ui codegen`).
+- **Gateway**: `internal/vkauth/` (the §3 verify), `internal/transcode` op `auth.vk`
+  (registered via `WithVKAuth(secret)` option; `DomainCode` → `invalid_vk_params`),
+  `internal/backendclient` `VKAuth` → `POST /api/v1/internal/sessions/vk`,
+  config `GATEWAY_VK_APP_SECRET`, SPA mount `/vk/` in `internal/connectsrv/server.go`.
+- **Backend**: `internal/account` `KindVK` + `ProvisionVK`/`vkSeed` + `confirmed` for platform
+  kinds; `internal/server/handlers_auth.go` `handleVKAuth` + route; migration
+  `00005_vk_identity.sql` (widen `identities_kind_chk` to include `'vk'`, expand-contract).
+- **UI**: `src/lib/vk.ts` (`onVKPath`/`vkLaunchParams`/`insideVK`/`vkInit`/`vkUserName` plus `vkAppId`/
+  `vkStartParam`/`vkShare`/`vkCopyText`/`vkOnScheme`), `app.svelte.ts` `bootVK` (+ deep-link routing
+  and VK scheme→theme) + the `/vk/` dispatch branch + shared `retryMiniAppBoot`, `codec.ts`
+  `encodeVKLogin`, `transport.ts`/`client.ts`/`mock/client.ts` `authVK`, `deeplink.ts` `vkShareLink`,
+  `Friends.svelte` (VK share/copy), `app.css` `--tg-safe-*` defaulting to `env(safe-area-inset-*)`.
+- **Edge/deploy**: `deploy/caddy/Caddyfile` `/vk` path; `GATEWAY_VK_APP_SECRET` in
+  `docker-compose.yml` + `.env.example` + `ci.yaml` (`TEST_…` secret) + `prod-deploy.yaml`
+  (`PROD_…` secret, deploy-main).
+- **Deferred**: payments (VK Pay / votes), native (Capacitor) VK, account-linking a vk identity to an
+  existing account, VK push. (Done after the launch+auth MVP — Group B: native share + clipboard via
+  the bridge, the friend-code deep link, the auto-theme follow, and the home-bar safe area.)
+
+## Sources
+
+- VKCOM/vk-bridge — <https://github.com/VKCOM/vk-bridge>
+- VKCOM/vk-apps-launch-params (canonical signature examples) — <https://github.com/VKCOM/vk-apps-launch-params>
+- kravetsone/vk-launch-params — <https://github.com/kravetsone/vk-launch-params>
+- SevereCloud/vksdk `vkapps.ParamsVerify` (Go reference) — <https://pkg.go.dev/github.com/SevereCloud/vksdk/v2/vkapps>
+- VK Mini Apps API — <https://github.com/VKCOM/vk-mini-apps-api>

.gitea/workflows/ci.yaml

@@ -26,12 +26,12 @@ on:
   push:
     branches: [development]
 
-# The dictionary release the test suite validates against — the current
+# The dictionary release. One Gitea variable is the single source of truth: the
-# scrabble-dictionary release. Centralised here so a release bump is one edit; the
+# test suite validates against it here (inherited by the unit/integration jobs) and
-# unit/integration jobs inherit it. The deploy job overrides it per contour with
+# both contours' deploy jobs seed a fresh volume with the same value. A release bump
-# vars.TEST_DICT_VERSION (the seed for a fresh volume), see deploy/README.md.
+# is one edit (the variable). See deploy/README.md.
 env:
-  DICT_VERSION: v1.2.1
+  DICT_VERSION: ${{ vars.DICT_VERSION }}
 
 jobs:
   # changes detects which areas a PR/push touched, so the test jobs can skip when
@@ -73,6 +73,9 @@ jobs:
             go=false; ui=false
             if echo "$files" | grep -qE '^(backend/|pkg/|gateway/|platform/|loadtest/|go\.work)'; then go=true; fi
             if echo "$files" | grep -qE '^ui/'; then ui=true; fi
+            # The render sidecar bundles ui/src/lib, so its dir rides the ui lane (the
+            # deploy's compose build picks it up either way).
+            if echo "$files" | grep -qE '^renderer/'; then ui=true; fi
             # A workflow or deploy change re-runs everything as a safety net.
             if echo "$files" | grep -qE '^(\.gitea/workflows/|deploy/)'; then go=true; ui=true; fi
           else
@@ -199,6 +202,14 @@ jobs:
       - name: Bundle-size budget
         run: node scripts/bundle-size.mjs
 
+      # The render sidecar executes the shared ui/src/lib/gameimage.ts on skia-canvas;
+      # its smoke test guards the bundling + skia seam (docs/TESTING.md).
+      - name: Render sidecar test
+        working-directory: renderer
+        run: |
+          pnpm install --frozen-lockfile
+          pnpm test
+
       - name: Install Playwright browsers
         run: pnpm exec playwright install chromium webkit
         timeout-minutes: 5
@@ -207,11 +218,66 @@ jobs:
         run: pnpm run test:e2e
         timeout-minutes: 5
 
+  # conformance proves the client's local move preview (the ported dawg reader +
+  # validator, ui/src/lib/dict) byte-for-byte against the authoritative Go engine:
+  # a Go step generates golden parity vectors from the release dictionaries, then the
+  # gated Vitest suite replays them. It spans both toolchains, so it runs whenever the
+  # Go engine side or the UI side changed.
+  conformance:
+    needs: changes
+    if: ${{ needs.changes.outputs.go == 'true' || needs.changes.outputs.ui == 'true' }}
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+    env:
+      GOPRIVATE: gitea.iliadenisov.ru/*
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Fetch dictionary DAWGs
+        run: |
+          mkdir -p "${GITHUB_WORKSPACE}/dawg"
+          curl -fsSL -o /tmp/dawg.tar.gz "https://gitea.iliadenisov.ru/developer/scrabble-dictionary/releases/download/${DICT_VERSION}/scrabble-dawg-${DICT_VERSION}.tar.gz"
+          tar xzf /tmp/dawg.tar.gz -C "${GITHUB_WORKSPACE}/dawg"
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.work
+          cache: true
+
+      - name: Generate golden parity vectors
+        run: |
+          go run ./backend/cmd/dictgen -dawg-dir "${GITHUB_WORKSPACE}/dawg" -out /tmp/dictgold
+          go run ./backend/cmd/validategen -dawg-dir "${GITHUB_WORKSPACE}/dawg" -out /tmp/validgold
+
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+
+      - name: Install pnpm
+        run: npm install -g pnpm@11.0.9
+
+      - name: Install deps
+        working-directory: ui
+        run: pnpm install --frozen-lockfile
+
+      - name: Local-eval conformance (reader + validator vs the Go engine)
+        working-directory: ui
+        env:
+          DICT_DAWG_DIR: ${{ github.workspace }}/dawg
+          DICT_GOLD_DIR: /tmp/dictgold
+          DICT_VALID_DIR: /tmp/validgold
+        run: pnpm exec vitest run src/lib/dict/
+
   # gate is the single branch-protection required check. It always runs and passes
   # only when each upstream job succeeded or was skipped (a path-filtered no-op),
   # failing the merge if any actually failed or was cancelled.
   gate:
-    needs: [unit, integration, ui]
+    needs: [unit, integration, ui, conformance]
     if: always()
     runs-on: ubuntu-latest
     defaults:
@@ -221,7 +287,7 @@ jobs:
       - name: Aggregate required checks
         run: |
           fail=
-          for r in "unit:${{ needs.unit.result }}" "integration:${{ needs.integration.result }}" "ui:${{ needs.ui.result }}"; do
+          for r in "unit:${{ needs.unit.result }}" "integration:${{ needs.integration.result }}" "ui:${{ needs.ui.result }}" "conformance:${{ needs.conformance.result }}"; do
             name="${r%%:*}"; res="${r#*:}"
             echo "$name = $res"
             case "$res" in
@@ -261,12 +327,47 @@ jobs:
           GRAFANA_ADMIN_PASSWORD: ${{ secrets.TEST_GRAFANA_ADMIN_PASSWORD }}
           TELEGRAM_BOT_TOKEN: ${{ secrets.TEST_TELEGRAM_BOT_TOKEN }}
           TELEGRAM_PROMO_BOT_TOKEN: ${{ secrets.TEST_TELEGRAM_PROMO_BOT_TOKEN }}
+          # VK Mini App protected key (offline HMAC for the launch-param signature); empty
+          # leaves the VK auth path (auth.vk) disabled until the operator sets the secret.
+          # One VK Mini App serves every contour -> unprefixed secret.
+          GATEWAY_VK_APP_SECRET: ${{ secrets.GATEWAY_VK_APP_SECRET }}
+          # VK ID web login (browser VK-identity linking): the VK ID "Web" app's protected key
+          # for the server-side confidential code exchange — a SEPARATE VK app from the Mini
+          # App above. One VK ID "Web" app serves every contour -> unprefixed secret.
+          GATEWAY_VK_ID_CLIENT_SECRET: ${{ secrets.GATEWAY_VK_ID_CLIENT_SECRET }}
+          # Planted honeytoken bearer: presenting it flags the caller (logs + a ban metric on
+          # test where the IP ban is off; a 24h IP ban on prod). Per-contour secret; empty = trap off.
+          GATEWAY_HONEYTOKEN: ${{ secrets.TEST_GATEWAY_HONEYTOKEN }}
+          # Signs the finished-game export download URLs (backend + compose interpolation).
+          EXPORT_SIGN_KEY: ${{ secrets.TEST_EXPORT_SIGN_KEY }}
+          # Transactional email via the shared Selectel relay: one account for every
+          # contour -> unprefixed host/port/tls/user/pass. Empty host leaves the backend
+          # on the log mailer (email disabled) but the contour still boots.
+          SMTP_RELAY_USER: ${{ secrets.SMTP_RELAY_USER }}
+          SMTP_RELAY_PASS: ${{ secrets.SMTP_RELAY_PASS }}
+          SMTP_RELAY_HOST: ${{ vars.SMTP_RELAY_HOST }}
+          SMTP_RELAY_PORT: ${{ vars.SMTP_RELAY_PORT }}
+          SMTP_RELAY_TLS: ${{ vars.SMTP_RELAY_TLS }}
+          SMTP_RELAY_FROM: ${{ vars.TEST_SMTP_RELAY_FROM }}
+          # Operator alerts: backend admin emails (new feedback / complaints) + Grafana
+          # infra alerts. Distinct senders + recipients; Grafana uses the relay's STARTTLS
+          # host:port. Empty leaves the alert worker off and Grafana SMTP disabled.
+          SMTP_RELAY_ADMIN_FROM: ${{ vars.TEST_SMTP_RELAY_ADMIN_FROM }}
+          ADMIN_EMAIL: ${{ vars.TEST_ADMIN_EMAIL }}
+          SMTP_RELAY_SERVICE_FROM: ${{ vars.TEST_SMTP_RELAY_SERVICE_FROM }}
+          SERVICE_EMAIL: ${{ vars.TEST_SERVICE_EMAIL }}
+          GRAFANA_SMTP_PORT: ${{ vars.GRAFANA_SMTP_PORT }}
+          GF_SMTP_ENABLED: ${{ vars.TEST_GF_SMTP_ENABLED }}
+          # Canonical public origin for links in the email (this contour's URL);
+          # required by the backend whenever SMTP_RELAY_HOST is set.
+          PUBLIC_BASE_URL: ${{ vars.TEST_PUBLIC_BASE_URL }}
           GM_BASICAUTH_USER: ${{ vars.TEST_GM_BASICAUTH_USER }}
-          GRAFANA_ROOT_URL: ${{ vars.TEST_GRAFANA_ROOT_URL }}
           CADDY_SITE_ADDRESS: ${{ vars.TEST_CADDY_SITE_ADDRESS }}
-          TELEGRAM_MINIAPP_URL: ${{ vars.TEST_TELEGRAM_MINIAPP_URL }}
+          # TELEGRAM_MINIAPP_URL, GRAFANA_ROOT_URL and VITE_VK_ID_REDIRECT_URL are derived
+          # from PUBLIC_BASE_URL in the run step below, not stored as their own variables.
           TELEGRAM_GAME_CHANNEL_ID: ${{ vars.TEST_TELEGRAM_GAME_CHANNEL_ID }}
           TELEGRAM_CHAT_ID: ${{ vars.TEST_TELEGRAM_CHAT_ID }}
+          TELEGRAM_SUPPORT_CHAT_ID: ${{ vars.TEST_TELEGRAM_SUPPORT_CHAT_ID }}
           TELEGRAM_BOT_USERNAME: ${{ vars.TEST_TELEGRAM_BOT_USERNAME }}
           # The promo button reuses the UI's Mini App link variable.
           TELEGRAM_BOT_LINK: ${{ vars.TEST_VITE_TELEGRAM_LINK }}
@@ -276,11 +377,16 @@ jobs:
           VITE_TELEGRAM_BOT_ID: ${{ vars.TEST_VITE_TELEGRAM_BOT_ID }}
           VITE_TELEGRAM_LINK: ${{ vars.TEST_VITE_TELEGRAM_LINK }}
           VITE_TELEGRAM_GAME_CHANNEL_NAME: ${{ vars.TEST_VITE_TELEGRAM_GAME_CHANNEL_NAME }}
-          VITE_GATEWAY_URL: ${{ vars.TEST_VITE_GATEWAY_URL }}
+          # VK Mini App landing link + VK ID "Web" app id: one value each serves every
-          # Unset vars render empty -> the compose ":-" defaults apply.
+          # contour -> unprefixed. VITE_VK_APP_ID also feeds the gateway (GATEWAY_VK_ID_APP_ID);
+          # the VK ID redirect URL is derived from PUBLIC_BASE_URL in the run step below.
+          VITE_VK_APP_LINK: ${{ vars.VITE_VK_APP_LINK }}
+          VITE_VK_APP_ID: ${{ vars.VITE_VK_APP_ID }}
+          # VITE_GATEWAY_URL omitted: the SPA is served same-origin, so it stays the
+          # compose ":-" empty default. Other unset vars likewise fall to their defaults.
           POSTGRES_DB: ${{ vars.TEST_POSTGRES_DB }}
           POSTGRES_USER: ${{ vars.TEST_POSTGRES_USER }}
-          DICT_VERSION: ${{ vars.TEST_DICT_VERSION }}
+          DICT_VERSION: ${{ vars.DICT_VERSION }}
           LOG_LEVEL: ${{ vars.TEST_LOG_LEVEL }}
         run: |
           # Seed the config files to a stable host path. The runner checks out into
@@ -291,8 +397,34 @@ jobs:
           conf="$HOME/.scrabble-deploy"
           rm -rf "$conf"
           mkdir -p "$conf"
-          cp -r caddy otelcol prometheus tempo grafana "$conf"/
+          cp -r caddy otelcol prometheus tempo grafana blackbox "$conf"/
           export SCRABBLE_CONFIG_DIR="$conf"
+          # Maintenance page for the redeploy window, mirroring prod-deploy.sh so the SPA
+          # overlay is exercised on the test contour too (not only prod). Raised just before
+          # the recreate and lowered once caddy is back (below); the trap clears it if the
+          # step fails so the contour never sticks in maintenance (and the reseed above wipes a
+          # stale flag anyway). The caddy-routed probes run in the NEXT step, after it is lowered.
+          maint_flag="$conf/caddy/on"
+          trap 'rm -f "$maint_flag"' EXIT
+          # Derive the public URLs from the one canonical origin instead of storing each as
+          # its own variable (paths are structural SPA routes / the Caddy /_gm sub-path).
+          # Exported before build so the VK ID redirect is baked into the SPA.
+          base="${PUBLIC_BASE_URL%/}"
+          export TELEGRAM_MINIAPP_URL="$base/telegram/"
+          export GRAFANA_ROOT_URL="$base/_gm/grafana/"
+          export VITE_VK_ID_REDIRECT_URL="$base/app/"
+          # Grafana's SMTP from_address must be a BARE address (it rejects the "Name" <addr>
+          # form the backend go-mail accepts) and validates it even when SMTP is disabled — a
+          # bad value crash-loops Grafana. Split the display-format SERVICE From into a bare
+          # address + name for Grafana; the backend keeps the full form.
+          svc_from="${SMTP_RELAY_SERVICE_FROM:-}"
+          case "$svc_from" in
+            *"<"*">"*)
+              export GRAFANA_SMTP_FROM_ADDRESS="$(printf '%s' "$svc_from" | sed -E 's/.*<([^>]+)>.*/\1/')"
+              export GRAFANA_SMTP_FROM_NAME="$(printf '%s' "$svc_from" | sed -E 's/[[:space:]]*<[^>]*>.*$//; s/^"//; s/"$//')" ;;
+            *)
+              export GRAFANA_SMTP_FROM_ADDRESS="$svc_from" ;;
+          esac
           # Bot-link mTLS material for the test contour: a private CA + gateway/bot
           # leaves (CN=gateway, the service name the bot dials). Prod supplies these
           # from PROD_ secrets instead. Regenerated each deploy; both ends redeploy
@@ -305,12 +437,23 @@ jobs:
           # bot on its own host instead (deploy/docker-compose.bot.yml), and the prod
           # main host omits both. Without the profile they would not start here.
           docker compose --ansi never --profile telegram-local build --progress plain
+          # Raise the maintenance page, THEN bring caddy onto the reseeded config mount so it
+          # actually carries the flag: the running caddy sits on the stale pre-reseed mount (the
+          # dir was rm'd + recreated — see the force-recreate note below), so a flag written to
+          # the new dir is invisible until caddy is recreated. With the fresh caddy up, an open
+          # SPA sees the 503 marker + overlay for the whole recreate window, not a bare reconnect.
+          : > "$maint_flag"
+          docker compose --ansi never up -d --force-recreate --no-deps caddy
           docker compose --ansi never --profile telegram-local up -d --remove-orphans
           # The config-only services bind-mount the reseeded config dir. A plain `up -d`
           # leaves them on the previous bind mount (the dir was rm'd + recreated), so a
-          # changed Caddyfile or Grafana dashboard is ignored — force-recreate them to
+          # changed Grafana dashboard is ignored — force-recreate them to pick up the fresh
-          # pick up the fresh config.
+          # config. (Caddy was already recreated above so it would carry the maintenance flag.)
-          docker compose --ansi never up -d --force-recreate --no-deps caddy otelcol prometheus tempo grafana
+          docker compose --ansi never up -d --force-recreate --no-deps otelcol prometheus tempo grafana
+          # Lower the maintenance page: services are back. An open SPA's poll now gets through
+          # (once the gateway finishes booting) and reloads into the fresh client; the caddy
+          # probes in the next step see 200. The EXIT trap is a backstop if we failed earlier.
+          rm -f "$maint_flag"
 
       - name: Probe the landing, gateway and backend
         run: |
@@ -336,6 +479,23 @@ jobs:
           docker logs --tail 50 scrabble-backend || true
           exit 1
 
+      - name: Probe the /dict edge route reaches the gateway
+        run: |
+          set -u
+          # The client fetches each game's dictionary blob at {edge}/dict/{variant}/{version}
+          # for the local move preview. If caddy does not route /dict to the gateway the request
+          # falls to the static landing and the client silently gets a non-dawg blob. Probed
+          # unauthenticated it must be the gateway's 401 (the route reaches the gateway), never a
+          # 404/200 from the landing catch-all.
+          out="$(docker run --rm --network edge alpine:3.20 wget -S -q -O /dev/null http://scrabble/dict/scrabble_en/v1 2>&1 || true)"
+          echo "$out" | grep -E "HTTP/" || true
+          if echo "$out" | grep -q " 401"; then
+            echo "ok: /dict reaches the gateway (401 unauthenticated)"
+          else
+            echo "FAIL: /dict did not reach the gateway (expected 401) — caddy route missing?"
+            exit 1
+          fi
+
       - name: Probe the Telegram validator and bot liveness
         run: |
           set -u

.gitea/workflows/prod-deploy.yaml

@@ -40,11 +40,22 @@ jobs:
       VITE_TELEGRAM_BOT_ID: ${{ vars.PROD_VITE_TELEGRAM_BOT_ID }}
       VITE_TELEGRAM_LINK: ${{ vars.PROD_VITE_TELEGRAM_LINK }}
       VITE_TELEGRAM_GAME_CHANNEL_NAME: ${{ vars.PROD_VITE_TELEGRAM_GAME_CHANNEL_NAME }}
-      VITE_GATEWAY_URL: ${{ vars.PROD_VITE_GATEWAY_URL }}
+      # VK Mini App link + VK ID "Web" app id: one value each serves every contour.
+      VITE_VK_APP_LINK: ${{ vars.VITE_VK_APP_LINK }}
+      VITE_VK_APP_ID: ${{ vars.VITE_VK_APP_ID }}
+      # VITE_GATEWAY_URL omitted: the SPA is served same-origin (compose ":-" default).
       POSTGRES_PASSWORD: ${{ secrets.PROD_POSTGRES_PASSWORD }}
       GM_BASICAUTH_HASH: ${{ secrets.PROD_GM_BASICAUTH_HASH }}
-      TELEGRAM_MINIAPP_URL: ${{ vars.PROD_TELEGRAM_MINIAPP_URL }}
+      # `docker compose build` interpolates the WHOLE compose file, so every :?-guarded
-      DICT_VERSION: ${{ vars.PROD_DICT_VERSION }}
+      # runtime var must be present at build even though it is not a build-arg — incl. the
+      # backend's EXPORT_SIGN_KEY (added with the finished-game export after v1.7.0, which is
+      # why the first v1.8.0 build tripped on it). POSTGRES_PASSWORD/GM_BASICAUTH_HASH above
+      # are here for the same reason; DICT_VERSION + the derived Mini App URL cover the rest.
+      EXPORT_SIGN_KEY: ${{ secrets.PROD_EXPORT_SIGN_KEY }}
+      # PUBLIC_BASE_URL drives the derived VK ID redirect (baked into the SPA) and the
+      # Mini App URL; both are computed in the build step, not stored variables.
+      PUBLIC_BASE_URL: ${{ vars.PROD_PUBLIC_BASE_URL }}
+      DICT_VERSION: ${{ vars.DICT_VERSION }}
     steps:
       - uses: actions/checkout@v4
         with:
@@ -58,10 +69,15 @@ jobs:
         working-directory: deploy
         run: |
           export TAG="${{ steps.ver.outputs.tag }}" APP_VERSION="${{ steps.ver.outputs.tag }}" SCRABBLE_CONFIG_DIR=.
-          # The four main-stack images via compose (reuses the build args, incl. VERSION);
+          # Derive the public URLs from the one canonical origin: the VK ID redirect is a
+          # build-arg baked into the SPA, and the Mini App URL satisfies the (profiled-out)
+          # bot service's compose ":?" guard during parse. See deploy/write-prod-env.sh.
+          base="${PUBLIC_BASE_URL%/}"
+          export VITE_VK_ID_REDIRECT_URL="$base/app/" TELEGRAM_MINIAPP_URL="$base/telegram/"
+          # The main-stack images via compose (reuses the build args, incl. VERSION);
           # the bot separately, since it is profiled out of the prod compose.
           docker compose -f docker-compose.yml -f docker-compose.prod.yml build
-          docker compose -f docker-compose.yml -f docker-compose.prod.yml push backend gateway landing validator
+          docker compose -f docker-compose.yml -f docker-compose.prod.yml push backend gateway landing validator renderer
           docker build -f ../platform/telegram/Dockerfile --target bot --build-arg VERSION="$TAG" -t "$REGISTRY/scrabble-telegram-bot:$TAG" ..
           docker push "$REGISTRY/scrabble-telegram-bot:$TAG"
 
@@ -82,17 +98,45 @@ jobs:
       GM_BASICAUTH_HASH: ${{ secrets.PROD_GM_BASICAUTH_HASH }}
       GRAFANA_ADMIN_PASSWORD: ${{ secrets.PROD_GRAFANA_ADMIN_PASSWORD }}
       TELEGRAM_BOT_TOKEN: ${{ secrets.PROD_TELEGRAM_BOT_TOKEN }}
+      GATEWAY_VK_APP_SECRET: ${{ secrets.GATEWAY_VK_APP_SECRET }}
+      # VK ID web login: the "Web" app id (the gateway reuses it as GATEWAY_VK_ID_APP_ID at
+      # runtime) + the app's protected key. Both shared across contours. The redirect URL is
+      # derived from PUBLIC_BASE_URL in deploy/write-prod-env.sh.
+      VITE_VK_APP_ID: ${{ vars.VITE_VK_APP_ID }}
+      GATEWAY_VK_ID_CLIENT_SECRET: ${{ secrets.GATEWAY_VK_ID_CLIENT_SECRET }}
+      # Planted honeytoken bearer: presenting it earns a 24h IP ban + a high-severity alarm.
+      # Per-contour secret; empty = trap off. Rendered by deploy/write-prod-env.sh.
+      GATEWAY_HONEYTOKEN: ${{ secrets.PROD_GATEWAY_HONEYTOKEN }}
+      # Signs the finished-game export download URLs (backend BACKEND_EXPORT_SIGN_KEY).
+      EXPORT_SIGN_KEY: ${{ secrets.PROD_EXPORT_SIGN_KEY }}
+      # Transactional email via the shared Selectel relay (confirm-codes): one account for
+      # every contour -> unprefixed host/port/tls/user/pass.
+      SMTP_RELAY_USER: ${{ secrets.SMTP_RELAY_USER }}
+      SMTP_RELAY_PASS: ${{ secrets.SMTP_RELAY_PASS }}
+      SMTP_RELAY_HOST: ${{ vars.SMTP_RELAY_HOST }}
+      SMTP_RELAY_PORT: ${{ vars.SMTP_RELAY_PORT }}
+      SMTP_RELAY_TLS: ${{ vars.SMTP_RELAY_TLS }}
+      SMTP_RELAY_FROM: ${{ vars.PROD_SMTP_RELAY_FROM }}
+      # Operator alerts: backend admin emails + Grafana infra alerts (distinct senders +
+      # recipients; Grafana uses the relay's STARTTLS host:port).
+      SMTP_RELAY_ADMIN_FROM: ${{ vars.PROD_SMTP_RELAY_ADMIN_FROM }}
+      ADMIN_EMAIL: ${{ vars.PROD_ADMIN_EMAIL }}
+      SMTP_RELAY_SERVICE_FROM: ${{ vars.PROD_SMTP_RELAY_SERVICE_FROM }}
+      SERVICE_EMAIL: ${{ vars.PROD_SERVICE_EMAIL }}
+      GRAFANA_SMTP_PORT: ${{ vars.GRAFANA_SMTP_PORT }}
+      GF_SMTP_ENABLED: ${{ vars.PROD_GF_SMTP_ENABLED }}
+      PUBLIC_BASE_URL: ${{ vars.PROD_PUBLIC_BASE_URL }}
       PROD_BOTLINK_CA: ${{ secrets.PROD_BOTLINK_CA }}
       PROD_BOTLINK_GATEWAY_CERT: ${{ secrets.PROD_BOTLINK_GATEWAY_CERT }}
       PROD_BOTLINK_GATEWAY_KEY: ${{ secrets.PROD_BOTLINK_GATEWAY_KEY }}
       GM_BASICAUTH_USER: ${{ vars.PROD_GM_BASICAUTH_USER }}
-      GRAFANA_ROOT_URL: ${{ vars.PROD_GRAFANA_ROOT_URL }}
       CADDY_SITE_ADDRESS: ${{ vars.PROD_CADDY_SITE_ADDRESS }}
       LOG_LEVEL: ${{ vars.PROD_LOG_LEVEL }}
-      DICT_VERSION: ${{ vars.PROD_DICT_VERSION }}
+      DICT_VERSION: ${{ vars.DICT_VERSION }}
       POSTGRES_DB: ${{ vars.PROD_POSTGRES_DB }}
       POSTGRES_USER: ${{ vars.PROD_POSTGRES_USER }}
-      TELEGRAM_MINIAPP_URL: ${{ vars.PROD_TELEGRAM_MINIAPP_URL }}
+      # TELEGRAM_MINIAPP_URL and GRAFANA_ROOT_URL are derived from PUBLIC_BASE_URL in
+      # deploy/write-prod-env.sh, not stored variables.
     steps:
       - uses: actions/checkout@v4
         with:
@@ -120,24 +164,8 @@ jobs:
         run: |
           umask 077
           mkdir -p stage/certs-main
-          cat > stage/env.sh <<EOF
+          # Shared with prod-rollback so the two paths render an identical runtime env.
-          export REGISTRY='$REGISTRY'
+          APP_VERSION="$TAG" bash deploy/write-prod-env.sh stage/env.sh
-          export SCRABBLE_CONFIG_DIR='/opt/scrabble'
-          export POSTGRES_DB='${POSTGRES_DB:-scrabble}'
-          export POSTGRES_USER='${POSTGRES_USER:-scrabble}'
-          export POSTGRES_PASSWORD='$POSTGRES_PASSWORD'
-          export GM_BASICAUTH_USER='${GM_BASICAUTH_USER:-gm}'
-          export GM_BASICAUTH_HASH='$GM_BASICAUTH_HASH'
-          export GRAFANA_ADMIN_PASSWORD='$GRAFANA_ADMIN_PASSWORD'
-          export GRAFANA_ROOT_URL='$GRAFANA_ROOT_URL'
-          export CADDY_SITE_ADDRESS='$CADDY_SITE_ADDRESS'
-          export LOG_LEVEL='${LOG_LEVEL:-info}'
-          export DICT_VERSION='$DICT_VERSION'
-          export APP_VERSION='$TAG'
-          export TELEGRAM_BOT_TOKEN='$TELEGRAM_BOT_TOKEN'
-          export TELEGRAM_MINIAPP_URL='$TELEGRAM_MINIAPP_URL'
-          export GATEWAY_ABUSE_BAN_ENABLED='true'
-          EOF
           printf '%s\n' "$PROD_BOTLINK_CA"           > stage/certs-main/ca.crt
           printf '%s\n' "$PROD_BOTLINK_GATEWAY_CERT" > stage/certs-main/gateway.crt
           printf '%s\n' "$PROD_BOTLINK_GATEWAY_KEY"  > stage/certs-main/gateway.key
@@ -148,7 +176,7 @@ jobs:
           ssh_main 'mkdir -p /opt/scrabble/compose'
           tar -C deploy -czf - docker-compose.yml docker-compose.prod.yml prod-deploy.sh \
             | ssh_main 'tar -C /opt/scrabble/compose -xzf -'
-          tar -C deploy -czf - caddy otelcol prometheus tempo grafana \
+          tar -C deploy -czf - caddy otelcol prometheus tempo grafana blackbox \
             | ssh_main 'tar -C /opt/scrabble -xzf -'
           tar -C stage -czf - certs-main \
             | ssh_main 'rm -rf /opt/scrabble/certs && mkdir -p /opt/scrabble/certs && tar -C /opt/scrabble/certs --strip-components=1 -xzf -'
@@ -176,9 +204,11 @@ jobs:
       PROD_BOTLINK_BOT_CERT: ${{ secrets.PROD_BOTLINK_BOT_CERT }}
       PROD_BOTLINK_BOT_KEY: ${{ secrets.PROD_BOTLINK_BOT_KEY }}
       LOG_LEVEL: ${{ vars.PROD_LOG_LEVEL }}
-      TELEGRAM_MINIAPP_URL: ${{ vars.PROD_TELEGRAM_MINIAPP_URL }}
+      # PUBLIC_BASE_URL drives the derived Mini App URL in deploy/write-prod-bot-env.sh.
+      PUBLIC_BASE_URL: ${{ vars.PROD_PUBLIC_BASE_URL }}
       TELEGRAM_GAME_CHANNEL_ID: ${{ vars.PROD_TELEGRAM_GAME_CHANNEL_ID }}
       TELEGRAM_CHAT_ID: ${{ vars.PROD_TELEGRAM_CHAT_ID }}
+      TELEGRAM_SUPPORT_CHAT_ID: ${{ vars.PROD_TELEGRAM_SUPPORT_CHAT_ID }}
       TELEGRAM_BOT_USERNAME: ${{ vars.PROD_TELEGRAM_BOT_USERNAME }}
       TELEGRAM_BOT_LINK: ${{ vars.PROD_VITE_TELEGRAM_LINK }}
     steps:
@@ -192,19 +222,8 @@ jobs:
         run: |
           umask 077
           mkdir -p stage/certs-bot
-          cat > stage/env.bot.sh <<EOF
+          # Shared with prod-rollback so the two paths render an identical bot env.
-          export SCRABBLE_CONFIG_DIR='/opt/scrabble'
+          BOT_IMAGE="$REGISTRY/scrabble-telegram-bot:$TAG" bash deploy/write-prod-bot-env.sh stage/env.bot.sh
-          export BOT_IMAGE='$REGISTRY/scrabble-telegram-bot:$TAG'
-          export BOTLINK_GATEWAY_ADDR='$MAIN_HOST:9443'
-          export TELEGRAM_BOT_TOKEN='$TELEGRAM_BOT_TOKEN'
-          export TELEGRAM_MINIAPP_URL='$TELEGRAM_MINIAPP_URL'
-          export TELEGRAM_GAME_CHANNEL_ID='$TELEGRAM_GAME_CHANNEL_ID'
-          export TELEGRAM_CHAT_ID='$TELEGRAM_CHAT_ID'
-          export TELEGRAM_PROMO_BOT_TOKEN='$TELEGRAM_PROMO_BOT_TOKEN'
-          export TELEGRAM_BOT_USERNAME='$TELEGRAM_BOT_USERNAME'
-          export TELEGRAM_BOT_LINK='$TELEGRAM_BOT_LINK'
-          export LOG_LEVEL='${LOG_LEVEL:-info}'
-          EOF
           printf '%s\n' "$PROD_BOTLINK_CA"       > stage/certs-bot/ca.crt
           printf '%s\n' "$PROD_BOTLINK_BOT_CERT" > stage/certs-bot/bot.crt
           printf '%s\n' "$PROD_BOTLINK_BOT_KEY"  > stage/certs-bot/bot.key

.gitea/workflows/prod-rollback.yaml

@@ -51,13 +51,32 @@ jobs:
       PROD_BOTLINK_GATEWAY_CERT: ${{ secrets.PROD_BOTLINK_GATEWAY_CERT }}
       PROD_BOTLINK_GATEWAY_KEY: ${{ secrets.PROD_BOTLINK_GATEWAY_KEY }}
       GM_BASICAUTH_USER: ${{ vars.PROD_GM_BASICAUTH_USER }}
-      GRAFANA_ROOT_URL: ${{ vars.PROD_GRAFANA_ROOT_URL }}
       CADDY_SITE_ADDRESS: ${{ vars.PROD_CADDY_SITE_ADDRESS }}
       LOG_LEVEL: ${{ vars.PROD_LOG_LEVEL }}
-      DICT_VERSION: ${{ vars.PROD_DICT_VERSION }}
+      DICT_VERSION: ${{ vars.DICT_VERSION }}
       POSTGRES_DB: ${{ vars.PROD_POSTGRES_DB }}
       POSTGRES_USER: ${{ vars.PROD_POSTGRES_USER }}
-      TELEGRAM_MINIAPP_URL: ${{ vars.PROD_TELEGRAM_MINIAPP_URL }}
+      PUBLIC_BASE_URL: ${{ vars.PROD_PUBLIC_BASE_URL }}
+      # Full runtime env — parity with prod-deploy's deploy-main so a rollback re-renders
+      # the SAME env.sh (email / VK login / Grafana alerts survive a rollback). TELEGRAM_MINIAPP_URL
+      # and GRAFANA_ROOT_URL are derived from PUBLIC_BASE_URL in deploy/write-prod-env.sh.
+      GATEWAY_VK_APP_SECRET: ${{ secrets.GATEWAY_VK_APP_SECRET }}
+      VITE_VK_APP_ID: ${{ vars.VITE_VK_APP_ID }}
+      GATEWAY_VK_ID_CLIENT_SECRET: ${{ secrets.GATEWAY_VK_ID_CLIENT_SECRET }}
+      GATEWAY_HONEYTOKEN: ${{ secrets.PROD_GATEWAY_HONEYTOKEN }}
+      EXPORT_SIGN_KEY: ${{ secrets.PROD_EXPORT_SIGN_KEY }}
+      SMTP_RELAY_USER: ${{ secrets.SMTP_RELAY_USER }}
+      SMTP_RELAY_PASS: ${{ secrets.SMTP_RELAY_PASS }}
+      SMTP_RELAY_HOST: ${{ vars.SMTP_RELAY_HOST }}
+      SMTP_RELAY_PORT: ${{ vars.SMTP_RELAY_PORT }}
+      SMTP_RELAY_TLS: ${{ vars.SMTP_RELAY_TLS }}
+      SMTP_RELAY_FROM: ${{ vars.PROD_SMTP_RELAY_FROM }}
+      SMTP_RELAY_ADMIN_FROM: ${{ vars.PROD_SMTP_RELAY_ADMIN_FROM }}
+      ADMIN_EMAIL: ${{ vars.PROD_ADMIN_EMAIL }}
+      SMTP_RELAY_SERVICE_FROM: ${{ vars.PROD_SMTP_RELAY_SERVICE_FROM }}
+      SERVICE_EMAIL: ${{ vars.PROD_SERVICE_EMAIL }}
+      GRAFANA_SMTP_PORT: ${{ vars.GRAFANA_SMTP_PORT }}
+      GF_SMTP_ENABLED: ${{ vars.PROD_GF_SMTP_ENABLED }}
       INPUT_TARGET: ${{ inputs.target_version }}
     steps:
       - uses: actions/checkout@v4
@@ -89,24 +108,9 @@ jobs:
         run: |
           umask 077
           mkdir -p stage/certs-main
-          cat > stage/env.sh <<EOF
+          # Same writer as prod-deploy's deploy-main -> the rollback re-renders the FULL
-          export REGISTRY='$REGISTRY'
+          # runtime env (not a subset), so email / VK login / Grafana alerts survive it.
-          export SCRABBLE_CONFIG_DIR='/opt/scrabble'
+          APP_VERSION="$TARGET" bash deploy/write-prod-env.sh stage/env.sh
-          export POSTGRES_DB='${POSTGRES_DB:-scrabble}'
-          export POSTGRES_USER='${POSTGRES_USER:-scrabble}'
-          export POSTGRES_PASSWORD='$POSTGRES_PASSWORD'
-          export GM_BASICAUTH_USER='${GM_BASICAUTH_USER:-gm}'
-          export GM_BASICAUTH_HASH='$GM_BASICAUTH_HASH'
-          export GRAFANA_ADMIN_PASSWORD='$GRAFANA_ADMIN_PASSWORD'
-          export GRAFANA_ROOT_URL='$GRAFANA_ROOT_URL'
-          export CADDY_SITE_ADDRESS='$CADDY_SITE_ADDRESS'
-          export LOG_LEVEL='${LOG_LEVEL:-info}'
-          export DICT_VERSION='$DICT_VERSION'
-          export APP_VERSION='$TARGET'
-          export TELEGRAM_BOT_TOKEN='$TELEGRAM_BOT_TOKEN'
-          export TELEGRAM_MINIAPP_URL='$TELEGRAM_MINIAPP_URL'
-          export GATEWAY_ABUSE_BAN_ENABLED='true'
-          EOF
           printf '%s\n' "$PROD_BOTLINK_CA"           > stage/certs-main/ca.crt
           printf '%s\n' "$PROD_BOTLINK_GATEWAY_CERT" > stage/certs-main/gateway.crt
           printf '%s\n' "$PROD_BOTLINK_GATEWAY_KEY"  > stage/certs-main/gateway.key
@@ -147,9 +151,11 @@ jobs:
       PROD_BOTLINK_BOT_CERT: ${{ secrets.PROD_BOTLINK_BOT_CERT }}
       PROD_BOTLINK_BOT_KEY: ${{ secrets.PROD_BOTLINK_BOT_KEY }}
       LOG_LEVEL: ${{ vars.PROD_LOG_LEVEL }}
-      TELEGRAM_MINIAPP_URL: ${{ vars.PROD_TELEGRAM_MINIAPP_URL }}
+      # PUBLIC_BASE_URL drives the derived Mini App URL; SUPPORT_CHAT_ID for parity with deploy.
+      PUBLIC_BASE_URL: ${{ vars.PROD_PUBLIC_BASE_URL }}
       TELEGRAM_GAME_CHANNEL_ID: ${{ vars.PROD_TELEGRAM_GAME_CHANNEL_ID }}
       TELEGRAM_CHAT_ID: ${{ vars.PROD_TELEGRAM_CHAT_ID }}
+      TELEGRAM_SUPPORT_CHAT_ID: ${{ vars.PROD_TELEGRAM_SUPPORT_CHAT_ID }}
       TELEGRAM_BOT_USERNAME: ${{ vars.PROD_TELEGRAM_BOT_USERNAME }}
       TELEGRAM_BOT_LINK: ${{ vars.PROD_VITE_TELEGRAM_LINK }}
     steps:
@@ -163,19 +169,8 @@ jobs:
         run: |
           umask 077
           mkdir -p stage/certs-bot
-          cat > stage/env.bot.sh <<EOF
+          # Same writer as prod-deploy's deploy-bot (parity; includes TELEGRAM_SUPPORT_CHAT_ID).
-          export SCRABBLE_CONFIG_DIR='/opt/scrabble'
+          BOT_IMAGE="$REGISTRY/scrabble-telegram-bot:$TARGET" bash deploy/write-prod-bot-env.sh stage/env.bot.sh
-          export BOT_IMAGE='$REGISTRY/scrabble-telegram-bot:$TARGET'
-          export BOTLINK_GATEWAY_ADDR='$MAIN_HOST:9443'
-          export TELEGRAM_BOT_TOKEN='$TELEGRAM_BOT_TOKEN'
-          export TELEGRAM_MINIAPP_URL='$TELEGRAM_MINIAPP_URL'
-          export TELEGRAM_GAME_CHANNEL_ID='$TELEGRAM_GAME_CHANNEL_ID'
-          export TELEGRAM_CHAT_ID='$TELEGRAM_CHAT_ID'
-          export TELEGRAM_PROMO_BOT_TOKEN='$TELEGRAM_PROMO_BOT_TOKEN'
-          export TELEGRAM_BOT_USERNAME='$TELEGRAM_BOT_USERNAME'
-          export TELEGRAM_BOT_LINK='$TELEGRAM_BOT_LINK'
-          export LOG_LEVEL='${LOG_LEVEL:-info}'
-          EOF
           printf '%s\n' "$PROD_BOTLINK_CA"       > stage/certs-bot/ca.crt
           printf '%s\n' "$PROD_BOTLINK_BOT_CERT" > stage/certs-bot/bot.crt
           printf '%s\n' "$PROD_BOTLINK_BOT_KEY"  > stage/certs-bot/bot.key

CLAUDE.md

@@ -125,9 +125,10 @@ gateway/                     # module scrabble/gateway: Connect-RPC edge, embeds
 ui/                          # Svelte + Vite SPA + landing (Node project, not in go.work)
 pkg/                         # shared: telemetry, version, wire/FlatBuffers, proto, mtls
 platform/telegram/           # Telegram side-service: cmd/validator (HMAC, no VPN) + cmd/bot (Bot API; dials gateway over reverse mTLS bot-link)
+renderer/                    # image-render sidecar (Node + skia-canvas): runs ui/src/lib/gameimage.ts server-side for the finished-game PNG export
 loadtest/                    # module scrabble/loadtest: the load/stress harness
 docs/  .gitea/workflows/  CLAUDE.md  README.md
-backend/Dockerfile gateway/Dockerfile platform/telegram/Dockerfile loadtest/Dockerfile  # multi-stage distroless; gateway/Dockerfile has the `landing` target, platform/telegram/Dockerfile has `validator`+`bot` targets
+backend/Dockerfile gateway/Dockerfile platform/telegram/Dockerfile loadtest/Dockerfile renderer/Dockerfile  # multi-stage distroless (renderer: node:22-slim + skia-canvas + fonts); gateway/Dockerfile has the `landing` target, platform/telegram/Dockerfile has `validator`+`bot` targets
 deploy/                      # docker-compose (+ prod overlay + bot host) + ansible provisioning + caddy + landing + otelcol (OTLP + docker_stats) + prometheus/tempo/grafana + node_exporter + postgres_exporter; prod-deploy.sh
 ```
 
@@ -143,8 +144,9 @@ go run ./backend/cmd/backend    # /healthz, /readyz on :8080
 
 cd ui && pnpm install && pnpm check && pnpm test:unit && pnpm build  # the UI
 pnpm start                      # UI mock mode: lobby -> game, no backend
+cd renderer && pnpm install && pnpm test  # image-render sidecar (bundles ui/src/lib/gameimage.ts, skia smoke)
 
-docker build -f backend/Dockerfile -t scrabble-backend .   # images; gateway embeds the SPA
+docker build --build-arg DICT_VERSION=v1.3.0 -f backend/Dockerfile -t scrabble-backend .  # DICT_VERSION required (no default); gateway embeds the SPA
 docker build -f gateway/Dockerfile --target gateway -t scrabble-gateway .
 docker build -f gateway/Dockerfile --target landing -t scrabble-landing .  # static landing
 docker compose -f deploy/docker-compose.yml config         # validate the full contour

README.md

@@ -89,7 +89,7 @@ observability stack (OTel Collector → Prometheus + Tempo → Grafana) + a fron
 services build from multi-stage distroless `*/Dockerfile`.
 
 ```sh
-docker build -f backend/Dockerfile -t scrabble-backend .   # pulls the DAWG release artifact
+docker build --build-arg DICT_VERSION=v1.3.0 -f backend/Dockerfile -t scrabble-backend .  # DICT_VERSION required; pulls that DAWG release artifact
 docker build -f gateway/Dockerfile -t scrabble-gateway .   # node stage builds + embeds the UI
 docker compose -f deploy/docker-compose.yml config         # validate (needs the TEST_/PROD_ env)
 ```

assets/icons/README.md

@@ -0,0 +1,41 @@
+# Erudit — site icons + Open Graph card
+
+The favicon set and the `og:image` link-preview card for the public landing
+(`ui/landing.html`) and the SPA shell (`ui/index.html`). Same design language as the
+[VK loading-screen logo](../vk/README.md): the wooden Erudit «Э» tile (score `8`),
+with the wordmark on the app's dark board green (`ui/src/app.css` tokens).
+
+| Output (committed to `ui/public/`) | Purpose |
+|------|---------|
+| `favicon.svg` | Vector favicon, transparent; tile + «Э» only (the score is illegible below ~32 px). |
+| `favicon.ico` | 32×32 PNG-in-ICO fallback (also answers the browsers' blind `/favicon.ico` probe). |
+| `apple-touch-icon.png` | 180×180 opaque full-bleed tile; iOS masks its own corners. |
+| `og-image.png` | 1200×630 card: tile + «Эрудит / Скрэббл — игра в слова». Referenced absolutely as `https://erudit-game.ru/og-image.png`. |
+
+## How it works
+
+`build/extract.js` extracts the needed glyph outlines (tile glyphs + every wordmark
+character) from LiberationSans (Arial-metric, the game's font stack) with their
+advance widths into `build/glyphs.json` (committed). `build/generate.js` composes
+plain SVG from those outlines — no font is needed at generation time — writes
+`favicon.svg` and rasterises the PNG/ICO outputs by screenshotting the SVGs with the
+`ui` package's Playwright chromium (`@playwright/test`); the `.ico` container is
+assembled in-script (a single PNG entry). Raster bytes therefore depend on the
+installed chromium version; the SVG sources are deterministic.
+
+## Regenerate
+
+Requirements: Node ≥ 18, `ui` installed (`pnpm install`, provides Playwright).
+`extract.js` additionally needs `opentype.js` (`npm i opentype.js`); **`generate.js`
+needs no extra packages**.
+
+```sh
+cd assets/icons
+
+# 1. (optional) re-extract the glyphs — only if the font or the wordmark changes:
+#    default font: /usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf
+node build/extract.js [/path/to/font.ttf]      # -> build/glyphs.json
+
+# 2. regenerate everything in ui/public/:
+node build/generate.js
+```

assets/icons/build/extract.js

@@ -0,0 +1,78 @@
+'use strict';
+// Extract the glyph outlines the site icons and the og-image wordmark need from a
+// grotesque font (LiberationSans = Arial-metric, matching the game's system-ui/Arial
+// stack) and emit cubic-bezier contours per character, baseline at y=0, y-down,
+// plus the advance width so generate.js can lay out words without the font.
+// Same outline conversion as ../../vk/build/extract.js, generalised to a char set.
+const opentype = require('opentype.js');
+const fs = require('fs');
+
+const FONT = process.argv[2] || '/usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf';
+const b = fs.readFileSync(FONT);
+const font = opentype.parse(b.buffer.slice(b.byteOffset, b.byteOffset + b.byteLength));
+const FS = 1000; // em scale
+
+// The tile glyphs («Э», «8») + every character of the og-image wordmark lines
+// («Эрудит», «Скрэббл — игра в слова»). The space carries only an advance.
+const CHARS = [...new Set('Э8рудитСкэббл—игра в слова')];
+
+function glyphData(ch) {
+  const g = font.charToGlyph(ch);
+  const p = g.getPath(0, 0, FS); // baseline at y=0, y-down
+  const contours = [];
+  let cur = null, prev = null;
+  for (const c of p.commands) {
+    if (c.type === 'M') {
+      if (cur) contours.push(cur);
+      cur = [{ v: [c.x, c.y], i: [c.x, c.y], o: [c.x, c.y] }];
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'L') {
+      cur.push({ v: [c.x, c.y], i: [c.x, c.y], o: [c.x, c.y] });
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'C') {
+      cur[cur.length - 1].o = [c.x1, c.y1];
+      cur.push({ v: [c.x, c.y], i: [c.x2, c.y2], o: [c.x, c.y] });
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'Q') {
+      const c1 = [prev.x + 2 / 3 * (c.x1 - prev.x), prev.y + 2 / 3 * (c.y1 - prev.y)];
+      const c2 = [c.x + 2 / 3 * (c.x1 - c.x), c.y + 2 / 3 * (c.y1 - c.y)];
+      cur[cur.length - 1].o = c1;
+      cur.push({ v: [c.x, c.y], i: c2, o: [c.x, c.y] });
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'Z') {
+      if (cur && cur.length > 1) {
+        const last = cur[cur.length - 1], first = cur[0];
+        if (Math.hypot(last.v[0] - first.v[0], last.v[1] - first.v[1]) < 1e-3) {
+          first.i = last.i; // fold the duplicate closing point into the first
+          cur.pop();
+        }
+      }
+      if (cur) { contours.push(cur); cur = null; }
+    }
+  }
+  if (cur) contours.push(cur);
+
+  let minx = Infinity, miny = Infinity, maxx = -Infinity, maxy = -Infinity;
+  const out = contours.map(ct => {
+    const v = [], i = [], o = [];
+    ct.forEach(pt => {
+      v.push(pt.v);
+      i.push([pt.i[0] - pt.v[0], pt.i[1] - pt.v[1]]);
+      o.push([pt.o[0] - pt.v[0], pt.o[1] - pt.v[1]]);
+      minx = Math.min(minx, pt.v[0]); maxx = Math.max(maxx, pt.v[0]);
+      miny = Math.min(miny, pt.v[1]); maxy = Math.max(maxy, pt.v[1]);
+    });
+    return { i, o, v, c: true };
+  });
+  const bbox = out.length
+    ? { x: minx, y: miny, w: maxx - minx, h: maxy - miny }
+    : { x: 0, y: 0, w: 0, h: 0 }; // the space has no outline
+  return { adv: g.advanceWidth * (FS / font.unitsPerEm), bbox, contours: out };
+}
+
+const glyphs = {};
+for (const ch of CHARS) glyphs[ch] = glyphData(ch);
+
+const out = __dirname + '/glyphs.json';
+fs.writeFileSync(out, JSON.stringify({ em: FS, glyphs }));
+console.log('wrote', out, fs.statSync(out).size, 'bytes;', CHARS.length, 'glyphs:', CHARS.join(''));

assets/icons/build/generate.js

@@ -0,0 +1,128 @@
+'use strict';
+// Site icons + the Open Graph card for the public landing, drawn from the same
+// design as ../../vk (the wooden Erudit tile: face «Э», score «8») and the app's
+// board palette (ui/src/app.css). Everything is composed as SVG from the committed
+// glyph outlines (build/extract.js -> glyphs.json), so no font is needed at build
+// time; the PNG/ICO rasters are screenshots taken with the ui package's Playwright
+// chromium (@playwright/test re-exports the browser API). Outputs go straight to
+// ui/public/:
+//   favicon.svg          96 viewBox, transparent, tile + «Э» (the score is illegible small)
+//   favicon.ico          32x32 PNG-in-ICO render of the same
+//   apple-touch-icon.png 180x180 opaque full-bleed tile (iOS masks its own corners)
+//   og-image.png         1200x630 card: tile + wordmark on the board green
+const fs = require('fs');
+const path = require('path');
+
+const G = JSON.parse(fs.readFileSync(path.join(__dirname, 'glyphs.json'), 'utf8'));
+const UI = path.resolve(__dirname, '../../../ui');
+const OUT = path.join(UI, 'public');
+
+// ---- palette (vk loader tile + app.css board tokens) ------------------------
+const FACE = '#D9B978', BORDER = '#B49559', GLYPH = '#1A1A1A';
+const BOARD_DARK = '#2a3330', TEXT = '#e7ece8', TEXT_MUTED = '#cdd6cf';
+
+// ---- glyph outlines -> SVG path data ----------------------------------------
+const r2 = n => Math.round(n * 100) / 100;
+// pathD renders one glyph's contours scaled by sc and translated by (tx, ty).
+function pathD(g, sc, tx, ty) {
+  const pt = (v, d) => `${r2(v[0] * sc + tx + d[0] * sc)} ${r2(v[1] * sc + ty + d[1] * sc)}`;
+  const Z = [0, 0];
+  return g.contours.map(ct => {
+    const n = ct.v.length;
+    let d = `M${pt(ct.v[0], Z)}`;
+    for (let k = 1; k <= n; k++) {
+      const a = k - 1, b = k % n;
+      d += `C${pt(ct.v[a], ct.o[a])} ${pt(ct.v[b], ct.i[b])} ${pt(ct.v[b], Z)}`;
+    }
+    return d + 'Z';
+  }).join('');
+}
+// glyphAt centres a glyph's bbox at (cx, cy) with the given pixel cap height, the
+// same placement rule as the vk loader's glyph(). stroke fattens it slightly.
+function glyphAt(ch, capPx, cx, cy, stroke, colour) {
+  const g = G.glyphs[ch], sc = capPx / g.bbox.h;
+  const d = pathD(g, sc, cx - (g.bbox.x + g.bbox.w / 2) * sc, cy - (g.bbox.y + g.bbox.h / 2) * sc);
+  return `<path d="${d}" fill="${colour}" stroke="${colour}" stroke-width="${r2(stroke)}"/>`;
+}
+// textLine lays out a string on a baseline from the per-glyph advances; capPx sets
+// the capital height (measured on «Э»). Returns the combined path + the width.
+function textLine(str, capPx, x, y, colour) {
+  const sc = capPx / G.glyphs['Э'].bbox.h;
+  let d = '', w = 0;
+  for (const ch of str) {
+    const g = G.glyphs[ch];
+    if (g.contours.length) d += pathD(g, sc, x + w, y);
+    w += g.adv * sc;
+  }
+  return { svg: `<path d="${d}" fill="${colour}"/>`, width: w };
+}
+// tile draws the rounded wooden tile centred at (cx, cy): size px wide/high, with
+// the vk loader's corner (6/52) and rim proportions, «Э» and optionally the «8».
+function tile(cx, cy, size, withScore) {
+  const h = size / 2, rx = size * (6 / 52), rim = size * (1.8 / 52);
+  let s = `<rect x="${r2(cx - h + rim / 2)}" y="${r2(cy - h + rim / 2)}" width="${r2(size - rim)}" height="${r2(size - rim)}" rx="${r2(rx)}" fill="${FACE}" stroke="${BORDER}" stroke-width="${r2(rim)}"/>`;
+  s += glyphAt('Э', size * (32 / 52), cx, cy - size * (1 / 52), size * (1 / 52), GLYPH);
+  if (withScore) s += glyphAt('8', size * (8.5 / 52), cx + size * (19.5 / 52), cy + size * (18.5 / 52), size * (0.5 / 52), GLYPH);
+  return s;
+}
+const svg = (w, h, body) => `<svg xmlns="http://www.w3.org/2000/svg" width="${w}" height="${h}" viewBox="0 0 ${w} ${h}">${body}</svg>`;
+
+// ---- favicon.svg (the committed vector master) -------------------------------
+const favicon = svg(96, 96, tile(48, 48, 88, false)) + '\n';
+
+// ---- apple-touch-icon: opaque full bleed, iOS applies its own corner mask ----
+const appleTouch = svg(180, 180,
+  `<rect width="180" height="180" fill="${FACE}"/>` +
+  `<rect x="8" y="8" width="164" height="164" rx="18" fill="none" stroke="${BORDER}" stroke-width="4"/>` +
+  glyphAt('Э', 100, 90, 88, 3, GLYPH) +
+  glyphAt('8', 26, 146, 142, 1.5, GLYPH));
+
+// ---- og-image: tile + wordmark, centred as one group on the board green ------
+function ogImage() {
+  const W = 1200, H = 630, tileSize = 340, gap = 84;
+  const l1 = textLine('Эрудит', 112, 0, 0, TEXT);
+  const l2 = textLine('Скрэббл — игра в слова', 44, 0, 0, TEXT_MUTED);
+  const textW = Math.max(l1.width, l2.width);
+  const left = (W - (tileSize + gap + textW)) / 2;
+  const tx = left + tileSize + gap;
+  // Two baselines around the vertical centre; the tile centre sits between them.
+  const b1 = 295, b2 = 408;
+  const body =
+    `<rect width="${W}" height="${H}" fill="${BOARD_DARK}"/>` +
+    tile(left + tileSize / 2, H / 2, tileSize, true) +
+    textLine('Эрудит', 112, tx, b1, TEXT).svg +
+    textLine('Скрэббл — игра в слова', 44, tx, b2, TEXT_MUTED).svg;
+  console.log(`og-image: text ${Math.round(textW)}px wide, group left ${Math.round(left)}px`);
+  return svg(W, H, body);
+}
+
+// ---- rasterisation (Playwright chromium from ui/node_modules) ----------------
+async function shoot(page, markup, w, h, transparent) {
+  await page.setViewportSize({ width: w, height: h });
+  await page.setContent(`<body style="margin:0">${markup}</body>`);
+  return page.screenshot({ omitBackground: transparent });
+}
+// icoFromPNG wraps one PNG as a single-entry .ico (ICONDIR + ICONDIRENTRY + PNG).
+function icoFromPNG(png, sizePx) {
+  const h = Buffer.alloc(22);
+  h.writeUInt16LE(0, 0); h.writeUInt16LE(1, 2); h.writeUInt16LE(1, 4); // icon, 1 image
+  h.writeUInt8(sizePx, 6); h.writeUInt8(sizePx, 7);                    // 32x32
+  h.writeUInt16LE(1, 10); h.writeUInt16LE(32, 12);                     // planes, 32bpp
+  h.writeUInt32LE(png.length, 14); h.writeUInt32LE(22, 18);            // size, offset
+  return Buffer.concat([h, png]);
+}
+
+(async () => {
+  fs.writeFileSync(path.join(OUT, 'favicon.svg'), favicon);
+  const { chromium } = require(path.join(UI, 'node_modules', '@playwright/test'));
+  const browser = await chromium.launch();
+  const page = await browser.newPage();
+  const fav32 = await shoot(page, svg(32, 32, tile(16, 16, 29.33, false)), 32, 32, true);
+  fs.writeFileSync(path.join(OUT, 'favicon.ico'), icoFromPNG(fav32, 32));
+  fs.writeFileSync(path.join(OUT, 'apple-touch-icon.png'), await shoot(page, appleTouch, 180, 180, false));
+  fs.writeFileSync(path.join(OUT, 'og-image.png'), await shoot(page, ogImage(), 1200, 630, false));
+  await browser.close();
+  for (const f of ['favicon.svg', 'favicon.ico', 'apple-touch-icon.png', 'og-image.png']) {
+    console.log('wrote', path.join(OUT, f), fs.statSync(path.join(OUT, f)).size, 'bytes');
+  }
+})();

assets/vk/README.md

@@ -0,0 +1,115 @@
+# Erudit — VK loading-screen logo (Lottie)
+
+Animated logo for the **VK app loading screen** (shown before the SPA assets load).
+The Erudit «Э» tile (score `8`) **drops in under gravity, lands with a soft squash —
+its left/right edges bulging into a cushion — then springs back up**, looping. A light
+"glint" is caught at the moment of the bounce.
+
+| File | Purpose |
+|------|---------|
+| `erudit-loader.json` | The Lottie to upload to VK. |
+| `erudit-loader-preview.gif` | Looping preview. Rendered on a green "baize" background **only in the preview** — the real asset has a **transparent** background. |
+| `build/` | The reproducible build pipeline (see *Regenerate*). |
+
+**VK requirements met:** 96×96 px · vector Lottie JSON · ≤ 24 KB (~11 KB) · seamless
+~1.1 s loop · transparent background.
+
+Design reference: a photo of the physical wooden Erudit tile.
+
+---
+
+## How it works
+
+A single flat layer holds the tile — a rounded-rect **face path**, the two glyphs, and
+a thin border — and everything is driven by that layer's transform plus a few colour /
+shape tracks. The anchor sits on the tile's **bottom edge**, so the squash happens
+against the floor.
+
+### Bounce (gravity)
+`position.y` of the bottom edge goes apex → floor → apex with **no dwell** (the apex is
+an instantaneous turn-around). The fall uses a strong **ease-in** (accelerate) and the
+rise a strong **ease-out** (decelerate), so it reads as real gravity. While falling fast
+the tile slightly **stretches** (tall+thin); that is the squash-and-stretch setup.
+
+### Soft cushion (squash)
+On contact the layer **squashes** (scaleY↓, scaleX↑) about the bottom anchor, with a
+touch of skew. Crucially the squash/cushion is **decoupled from the fall speed** — it
+eases in and out *slowly* (`ES`), so the landing feels soft even though the fall is
+fast. The squash is deliberately gentle (≈ 86 % / 112 %).
+
+### The cushion shape (the hard part)
+The face is **not** a plain rounded rect — it is a path whose left/right contour bows
+out into a convex cushion on impact:
+- the rest rounded-rect outline is sampled (fine corner arcs + edge mids), and on impact
+  every point is pushed outward by a smooth **barrel** profile `f(y) = b·(1 − (y/HH)²)`
+  (max at the middle, fading to zero at the top/bottom);
+- so the **whole side — corners included — bows out as one piece**, never just the
+  straight middle;
+- bezier handles are computed as a **chordal spline** (handle length ∝ the adjacent
+  chord), which stays smooth across the uneven corner/edge point spacing. This is what
+  keeps the corner↔cushion junction kink-free — both at rest and fully bulged — which a
+  naïve uniform Catmull-Rom (or moving discrete points with fixed tangents) does not.
+
+### Glint
+At the bounce the face flashes a little lighter (`FACE_GLINT`) and the glyphs warm
+toward brown-red (`BLACK_LIT`), then settle back. A cheap, warm "catch the light".
+
+### Border & background
+The tile carries a thin static **border** a touch darker than the face (`BORDER`) so it
+reads on any background. The **green baize background is added only when rendering the
+preview GIF** — the Lottie itself is transparent.
+
+### Player compatibility
+Only plain 2-D shapes (`ddd:0`) — no 3-D layers, expressions or effects — so every
+Lottie player (lottie-web on the web, rlottie on native) renders it identically.
+
+---
+
+## Glyphs
+
+`Э` (U+042D) and `8` are **real outlines from LiberationSans-Regular** — metric-
+compatible with Arial, matching the game's `--font: system-ui … Arial` stack
+(see `ui/src/app.css`). `build/extract.js` pulls the contours into `build/glyphs.json`
+as Lottie cubic paths; a hair of same-colour stroke adds a touch of weight.
+
+---
+
+## Regenerate
+
+Requirements: Node ≥ 18. `extract.js` additionally needs `opentype.js`
+(`npm i opentype.js`); **`generate.js` has no dependencies**.
+
+```sh
+cd assets/vk
+
+# 1. (optional) re-extract the glyphs — only if you change the font:
+#    default font: /usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf
+node build/extract.js [/path/to/font.ttf]      # -> build/glyphs.json
+
+# 2. build the animation (reads build/glyphs.json):
+node build/generate.js erudit-loader.json      # -> erudit-loader.json
+
+# 3. (optional) live preview — needs lottie-web (npm i lottie-web):
+node build/build-preview.js erudit-loader.json preview.html
+#    then open preview.html in a browser.
+```
+
+The preview GIF is assembled by rendering the Lottie frame-by-frame (lottie-web canvas,
+filled with the green baize) and stitching with `ffmpeg`; the live HTML preview is the
+quickest way to eyeball changes.
+
+## Tunables (top of `build/generate.js`)
+
+| Symbol | Meaning |
+|--------|---------|
+| `OP`, `FR` | loop length (frames) / fps — overall speed |
+| `T_HIT / T_PEAK / T_LIFT / T_REC` | beats: contact / squash peak / lift-off / cushion recovered |
+| `EI / EO / ES` | easings: fast fall / fast rise / slow soft cushion |
+| `APEX`, `FLOOR` | bottom-edge screen-y at the top of the bounce / at rest |
+| `HW`, `HH`, `CR` | tile half-width / half-height / corner radius |
+| `scl` squash values | the squash amount (scaleX↑ / scaleY↓) |
+| `bulge` `b` | cushion depth (how far the sides bow out) |
+| `FACE / FACE_GLINT` | wood face / glint flash |
+| `BORDER` | tile rim colour |
+| `BLACK / BLACK_LIT` | glyph / glyph-at-glint (brown-red) |
+| preview bg `#3C7858` | the green-baize colour used **only** in the GIF |

assets/vk/build/build-preview.js

@@ -0,0 +1,31 @@
+'use strict';
+const fs = require('fs');
+const data = fs.readFileSync(process.argv[2] || 'erudit.json', 'utf8');
+const lottiePath = __dirname + '/node_modules/lottie-web/build/player/lottie.min.js';
+const html = `<!doctype html><html><head><meta charset="utf8"><style>
+body{margin:0;background:#2b2b2b;font-family:sans-serif;color:#ccc}
+.row{display:flex;gap:18px;padding:18px;align-items:flex-end;flex-wrap:wrap}
+.cell{text-align:center}
+.chk{background-image:linear-gradient(45deg,#8a8a8a 25%,transparent 25%),linear-gradient(-45deg,#8a8a8a 25%,transparent 25%),linear-gradient(45deg,transparent 75%,#8a8a8a 75%),linear-gradient(-45deg,transparent 75%,#8a8a8a 75%);background-size:16px 16px;background-position:0 0,0 8px,8px -8px,-8px 0;background-color:#b5b5b5}
+.s96{width:96px;height:96px}.big{width:336px;height:336px}small{font-size:11px}
+</style></head><body><div class="row" id="row"></div>
+<script src="./lottie.min.js"></script>
+<script>
+const animationData=${data};window.AD=animationData;
+const row=document.getElementById('row');window.anims=[];
+function make(cls,frame,label){
+  const cell=document.createElement('div');cell.className='cell';
+  const box=document.createElement('div');box.className='chk '+cls;cell.appendChild(box);
+  cell.appendChild(document.createElement('br'));
+  const cap=document.createElement('small');cap.textContent=label;cell.appendChild(cap);
+  row.appendChild(cell);
+  const a=lottie.loadAnimation({container:box,renderer:'svg',loop:false,autoplay:false,animationData:JSON.parse(JSON.stringify(animationData))});
+  a.addEventListener('DOMLoaded',()=>a.goToAndStop(frame,true));
+  window.anims.push(a);
+}
+[0,22,45,68].forEach(f=>make('s96',f,'f'+f));
+make('big',22,'f22 x3.5');
+window.__ready=true;
+</script></body></html>`;
+fs.writeFileSync(process.argv[3] || 'preview.html', html);
+console.log('wrote', process.argv[3] || 'preview.html');

assets/vk/build/extract.js

@@ -0,0 +1,67 @@
+'use strict';
+// Extract the Cyrillic "Э" (U+042D) and the digit "8" outlines from a grotesque
+// font (LiberationSans = Arial-metric, matching the game's system-ui/Arial stack)
+// and emit Lottie cubic-bezier contours, centred at the origin, y-down.
+const opentype = require('opentype.js');
+const fs = require('fs');
+
+const FONT = process.argv[2] || '/usr/share/fonts/truetype/liberation/LiberationSans-Regular.ttf';
+const b = fs.readFileSync(FONT);
+const font = opentype.parse(b.buffer.slice(b.byteOffset, b.byteOffset + b.byteLength));
+const FS = 1000; // em scale
+
+function glyphContours(ch) {
+  const p = font.charToGlyph(ch).getPath(0, 0, FS); // baseline at y=0, y-down
+  const contours = [];
+  let cur = null, prev = null;
+  for (const c of p.commands) {
+    if (c.type === 'M') {
+      if (cur) contours.push(cur);
+      cur = [{ v: [c.x, c.y], i: [c.x, c.y], o: [c.x, c.y] }];
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'L') {
+      cur.push({ v: [c.x, c.y], i: [c.x, c.y], o: [c.x, c.y] });
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'C') {
+      cur[cur.length - 1].o = [c.x1, c.y1];
+      cur.push({ v: [c.x, c.y], i: [c.x2, c.y2], o: [c.x, c.y] });
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'Q') {
+      const c1 = [prev.x + 2 / 3 * (c.x1 - prev.x), prev.y + 2 / 3 * (c.y1 - prev.y)];
+      const c2 = [c.x + 2 / 3 * (c.x1 - c.x), c.y + 2 / 3 * (c.y1 - c.y)];
+      cur[cur.length - 1].o = c1;
+      cur.push({ v: [c.x, c.y], i: c2, o: [c.x, c.y] });
+      prev = { x: c.x, y: c.y };
+    } else if (c.type === 'Z') {
+      if (cur && cur.length > 1) {
+        const last = cur[cur.length - 1], first = cur[0];
+        if (Math.hypot(last.v[0] - first.v[0], last.v[1] - first.v[1]) < 1e-3) {
+          first.i = last.i;            // fold the duplicate closing point into the first
+          cur.pop();
+        }
+      }
+      if (cur) { contours.push(cur); cur = null; }
+    }
+  }
+  if (cur) contours.push(cur);
+
+  let minx = Infinity, miny = Infinity, maxx = -Infinity, maxy = -Infinity;
+  const out = contours.map(ct => {
+    const v = [], i = [], o = [];
+    ct.forEach(pt => {
+      v.push(pt.v);
+      i.push([pt.i[0] - pt.v[0], pt.i[1] - pt.v[1]]);
+      o.push([pt.o[0] - pt.v[0], pt.o[1] - pt.v[1]]);
+      minx = Math.min(minx, pt.v[0]); maxx = Math.max(maxx, pt.v[0]);
+      miny = Math.min(miny, pt.v[1]); maxy = Math.max(maxy, pt.v[1]);
+    });
+    return { i, o, v, c: true };
+  });
+  return { contours: out, bbox: { x: minx, y: miny, w: maxx - minx, h: maxy - miny } };
+}
+
+const E = glyphContours('Э');
+const D8 = glyphContours('8');
+fs.writeFileSync('glyphs.json', JSON.stringify({ em: FS, E, D8 }));
+console.log('Э bbox', E.bbox, 'contours', E.contours.map(c => c.v.length));
+console.log('8 bbox', D8.bbox, 'contours', D8.contours.map(c => c.v.length));

assets/vk/build/generate.js

@@ -0,0 +1,153 @@
+'use strict';
+// VK preloader Lottie: a flat wooden Erudit tile ("Э" + score "8") that drops in
+// under gravity, squashes on impact (convex cushion bulging out the left/right edges
+// + a touch of skew), and springs back up — looping. A light "glint" is caught at the
+// moment of the bounce. Pure 2D shapes (ddd:0). Glyphs are real LiberationSans
+// outlines (Arial-metric, = the game's font stack); see extract.js -> glyphs.json.
+const fs = require('fs');
+const G = JSON.parse(fs.readFileSync(__dirname + '/glyphs.json', 'utf8'));
+
+// ---- canvas / timing -------------------------------------------------------
+const W = 96, H = 96, cx = 48;
+const FR = 30, OP = 34;                      // ~1.13 s loop (dynamic, 25% faster)
+// keyframe beats (frames): fast fall -> soft squash -> lift -> fast rise -> apex (no dwell)
+const T_HIT = 13, T_PEAK = 18, T_LIFT = 19, T_REC = 28;
+
+// ---- geometry --------------------------------------------------------------
+const HW = 26, HH = 26, CR = 6;              // tile half-width / half-height / corner radius
+const FLOOR = 90, APEX = 60;                 // bottom-centre screen-y at rest / at the top of the bounce
+
+// ---- palette ---------------------------------------------------------------
+const col = h => [parseInt(h.slice(1,3),16)/255, parseInt(h.slice(3,5),16)/255, parseInt(h.slice(5,7),16)/255];
+const FACE = col('#D9B978');                 // wood face (flat)
+const FACE_GLINT = col('#E7CD95');           // face flash caught on impact (gentle, not blinding)
+const BORDER = col('#B49559');               // tile rim: a touch darker than the face, reads on any bg
+const BLACK = col('#1A1A1A');
+const BLACK_LIT = col('#421A0B');            // glyph warms to brown-red on the glint
+const lerp = (a, b, t) => a.map((v, i) => v + (b[i] - v) * t);
+
+// ---- property / easing helpers ---------------------------------------------
+const still = v => ({ a: 0, k: v });
+const EI = { o: { x: [0.82], y: [0] }, i: { x: [1], y: [1] } };  // strong accelerate (gravity fall)
+const EO = { o: { x: [0], y: [0] }, i: { x: [0.18], y: [1] } };  // strong decelerate (rise to apex)
+const ES = { o: { x: [0.42], y: [0] }, i: { x: [0.58], y: [1] } }; // soft/slow (the cushion)
+function anim(samples) {                      // samples: {t, v, e?} ; e = easing toward the NEXT key
+  return { a: 1, k: samples.map((s, idx) => {
+    const kf = { t: s.t, s: s.v };
+    if (idx < samples.length - 1) { const e = s.e || ES; kf.o = e.o; kf.i = e.i; }
+    return kf;
+  }) };
+}
+const animColor = s => anim(s.map(x => ({ t: x.t, v: [...x.v, 1], e: x.e })));
+
+// ---- shape helpers ---------------------------------------------------------
+const tr = () => ({ ty: 'tr', p: still([0,0]), a: still([0,0]), s: still([100,100]), r: still(0), o: still(100) });
+const grp = (items, nm) => ({ ty: 'gr', it: [...items, tr()], nm });
+const fill = c => ({ ty: 'fl', c, o: still(100), r: 1, bm: 0 });
+const stroke = (c,w) => ({ ty: 'st', c: still(c), o: still(100), w: still(w), lc: 2, lj: 2, ml: 4, bm: 0 });
+function glyph(gd, hpx, px, py, bold, colour, nm) {  // font glyph -> filled+stroked group
+  const sc = hpx / gd.bbox.h;
+  const bcx = gd.bbox.x + gd.bbox.w / 2, bcy = gd.bbox.y + gd.bbox.h / 2;
+  const shapes = gd.contours.map(ct => ({
+    ty: 'sh', d: 1, ks: still({
+      i: ct.i.map(p => [p[0]*sc, p[1]*sc]), o: ct.o.map(p => [p[0]*sc, p[1]*sc]),
+      v: ct.v.map(p => [(p[0]-bcx)*sc + px, (p[1]-bcy)*sc + py]), c: true,
+    }),
+  }));
+  return grp([...shapes, fill(colour), stroke(BLACK, bold)], nm);
+}
+
+// Sample the rest rounded-rect outline (clockwise): fine corner arcs + one mid point
+// per straight edge, so a smooth interpolant reproduces it cleanly.
+function arc(ccx, ccy, a0, a1, n) {
+  const out = [];
+  for (let i = 0; i < n; i++) { const a = (a0 + (a1 - a0) * i / (n - 1)) * Math.PI / 180; out.push([ccx + CR*Math.cos(a), ccy + CR*Math.sin(a)]); }
+  return out;
+}
+const REST = (() => {
+  const NC = 7, yi = HH - CR, xi = HW - CR;
+  const C = [ arc(xi,-yi,-90,0,NC), arc(xi,yi,0,90,NC), arc(-xi,yi,90,180,NC), arc(-xi,-yi,180,270,NC) ];
+  const pts = [];
+  for (let k = 0; k < 4; k++) {
+    pts.push(...C[k]);
+    const a = C[k][NC-1], b = C[(k+1)%4][0];
+    pts.push([(a[0]+b[0])/2, (a[1]+b[1])/2]);   // straight-edge mid point (keeps the edge straight)
+  }
+  return pts;
+})();
+// The whole left/right contour (corners + side) bows out by one smooth barrel profile;
+// Catmull-Rom tangents (from neighbours) make every junction C1-smooth -> no kink, the
+// corners follow the cushion and the cushion melts into the corners, bulged or not.
+function facePath(b) {
+  const f = y => b * (1 - (y/HH) * (y/HH));                       // 0 at top/bottom, max at the middle
+  const V = REST.map(([x, y]) => [x + Math.sign(x) * f(y), y]);   // push the sides out, top/bottom stay
+  const n = V.length, I = [], O = [];
+  for (let k = 0; k < n; k++) {
+    const p0 = V[(k-1+n)%n], p1 = V[k], p2 = V[(k+1)%n];
+    let dx = p2[0]-p0[0], dy = p2[1]-p0[1];                       // tangent direction (neighbours)
+    const dl = Math.hypot(dx, dy) || 1; dx /= dl; dy /= dl;
+    const ln = Math.hypot(p2[0]-p1[0], p2[1]-p1[1]) / 3;          // handles ~ 1/3 of the adjacent chord
+    const lp = Math.hypot(p1[0]-p0[0], p1[1]-p0[1]) / 3;          // -> chordal spline, no overshoot/facets
+    O.push([dx*ln, dy*ln]); I.push([-dx*lp, -dy*lp]);
+  }
+  return { i: I, o: O, v: V, c: true };
+}
+const facePathKeys = samples => ({ a: 1, k: samples.map((s, idx) => {
+  const kf = { t: s.t, s: [facePath(s.b)] };
+  if (idx < samples.length - 1) { const e = s.e || ES; kf.o = e.o; kf.i = e.i; }
+  return kf;
+}) });
+
+// ---- animation tracks ------------------------------------------------------
+// bottom-centre screen-y (the tile rests/squashes on its bottom edge)
+const posY = anim([
+  { t: 0,      v: [cx, APEX, 0],  e: EI },           // apex -> immediately falls (no dwell)
+  { t: T_HIT,  v: [cx, FLOOR, 0], e: ES },           // FAST fall (accelerate) -> floor
+  { t: T_LIFT, v: [cx, FLOOR, 0], e: EO },           // sit on the floor while the cushion absorbs
+  { t: OP,     v: [cx, APEX, 0] },                   // FAST rise (decelerate) -> apex = loop start
+]);
+// scale about the bottom anchor: stretch while falling, gentle/slow cushion squash on impact
+const scl = anim([
+  { t: 0,        v: [100, 100, 100], e: ES },
+  { t: T_HIT-5,  v: [95, 106, 100], e: ES },         // stretch while falling fast
+  { t: T_HIT,    v: [104, 95, 100], e: ES },         // touch down
+  { t: T_PEAK,   v: [112, 86, 100], e: ES },         // soft squash peak (gentler, less plче)
+  { t: T_REC,    v: [100, 100, 100], e: ES },        // slow cushion release -> soft landing
+  { t: OP,       v: [100, 100, 100] },
+]);
+// a touch of skew through the squash (organic deform), back to 0
+const skw = anim([
+  { t: T_HIT, v: [0], e: ES }, { t: T_PEAK, v: [4], e: ES }, { t: T_REC, v: [0] }, { t: OP, v: [0] },
+]);
+// left/right cushion bulge: 0 -> gentle peak -> 0 (never inward)
+const bulge = facePathKeys([
+  { t: T_HIT, b: 0, e: ES }, { t: T_PEAK, b: 4, e: ES }, { t: T_REC, b: 0 }, { t: OP, b: 0 },
+]);
+// glint: face + glyph catch the light at the bounce
+const faceCol = animColor([
+  { t: T_HIT-2, v: FACE, e: ES }, { t: T_PEAK, v: FACE_GLINT, e: ES }, { t: T_REC, v: FACE }, { t: OP, v: FACE },
+]);
+const glyphCol = animColor([
+  { t: T_HIT-2, v: BLACK, e: ES }, { t: T_PEAK, v: BLACK_LIT, e: ES }, { t: T_REC, v: BLACK }, { t: OP, v: BLACK },
+]);
+
+// ---- layer (face + glyphs share the bounce/squash transform) ---------------
+const faceShape = grp([ { ty: 'sh', d: 1, ks: bulge }, fill(faceCol), stroke(BORDER, 1.8) ], 'face');
+const glyphE = glyph(G.E,  32, 0, -1, 1.0, glyphCol, 'E');                 // centred Э
+const glyph8 = glyph(G.D8, 8.5, HW-6.5, HH-7.5, 0.5, glyphCol, 'score');   // 8 in the corner
+
+const tile = {
+  ddd: 0, ind: 1, ty: 4, nm: 'tile', sr: 1,
+  ks: { o: still(100), r: still(0), p: posY, a: still([0, HH, 0]), s: scl, sk: skw, sa: still(0) },
+  ao: 0, shapes: [ glyph8, glyphE, faceShape ], ip: 0, op: OP, st: 0, bm: 0,
+};
+
+const root = {
+  v: '5.7.4', fr: FR, ip: 0, op: OP, w: W, h: H, nm: 'erudit-vk-loader', ddd: 0,
+  assets: [], layers: [ tile ], markers: [],
+};
+
+const out = process.argv[2] || 'erudit.json';
+const round = (k, v) => (typeof v === 'number' ? Math.round(v * 100) / 100 : v);
+fs.writeFileSync(out, JSON.stringify(root, round));
+console.log('wrote', out, fs.statSync(out).size, 'bytes');

backend/Dockerfile

@@ -7,12 +7,14 @@
 # (GOPRIVATE), so the build stage needs git and network.
 #
 # Build from the repository root so go.work, go.work.sum, pkg/ and backend/ are all
-# in the Docker context:
+# in the Docker context. DICT_VERSION has no default — the caller supplies the
-#   docker build -f backend/Dockerfile -t scrabble-backend .
+# scrabble-dictionary release tag (compose/CI pass it; see deploy/README.md
+# "Bumping the dictionary version"):
+#   docker build --build-arg DICT_VERSION=v1.3.0 -f backend/Dockerfile -t scrabble-backend .
 
 # --- dictionary artifact -----------------------------------------------------
 FROM alpine:3.20 AS dawg
-ARG DICT_VERSION=v1.2.1
+ARG DICT_VERSION
 RUN apk add --no-cache curl tar
 RUN mkdir -p /dawg \
  && curl -fsSL -o /tmp/dawg.tar.gz \
@@ -42,7 +44,7 @@ FROM gcr.io/distroless/static-debian12:nonroot
 # Re-declare the build arg in this stage so it labels the seed dictionary. One
 # DICT_VERSION drives both the artifact the dawg stage downloads and the version
 # label the binary pins, so the resident version equals the release tag.
-ARG DICT_VERSION=v1.2.1
+ARG DICT_VERSION
 COPY --from=build /out/backend /usr/local/bin/backend
 # Own the seed dictionary as the nonroot runtime user (UID 65532): a named volume
 # mounted at /opt/dawg inherits this ownership on first use, so the admin console

backend/README.md

@@ -43,8 +43,10 @@ per-user blocks, and per-game chat with nudges folded in as a message kind; chat
 messages are length-capped, content-filtered (no links/emails/phone numbers,
 including obfuscated forms) and stored with the sender's IP. Each message carries an
 `unread_seats` read bitmask (a set bit per recipient seat still to read it); `MarkRead`
-clears a reader's bit when they open the move history or chat, and a wired `NudgeClearer`
+clears a reader's bit when they open the move history or chat, a wired `NudgeClearer`
-clears a nudge when its recipient moves — both record the publish-to-read latency.
+clears a nudge when its recipient moves, and a wired `NudgeExpirer` clears **all** of a game's
+nudges when it finishes (any completion path) — the first two record the publish-to-read latency,
+the completion expiry does not (it is not a read); chat messages stay unread on completion.
 A friend request (or block) aimed at a **disguised pooled robot** is recorded per game+seat
 in `robot_friend_requests` / `robot_blocks`, never against the shared robot account; a
 background reaper drops a robot friend request once its game has been finished for **7 days**.
@@ -212,11 +214,13 @@ internal/banview/    # gateway active-ban mirror: the console's Active IP bans p
 | `BACKEND_LOBBY_ROBOT_WAIT` | `10s` | Auto-match wait before a robot is substituted for a missing human. |
 | `BACKEND_LOBBY_REAPER_INTERVAL` | `1s` | How often the substitution reaper scans for over-waited players. |
 | `BACKEND_ROBOT_DRIVE_INTERVAL` | `30s` | How often the robot driver scans for due robot turns. |
-| `BACKEND_SMTP_HOST` | — | Email relay host. **Empty selects the development log mailer** (the confirm-code is logged, not sent). |
+| `BACKEND_SMTP_HOST` | — | Confirm-code relay host. **Empty selects the development log mailer** (the code is logged, not sent). |
-| `BACKEND_SMTP_PORT` | `587` | Email relay port. |
+| `BACKEND_SMTP_PORT` | `587` | Relay port. No client certificate is needed (the server cert is validated against the system roots). |
-| `BACKEND_SMTP_USERNAME` | — | SMTP user; empty relays without authentication. |
+| `BACKEND_SMTP_TLS` | — | Transport security: `ssl` (implicit TLS from connect) or `starttls`. Empty derives it from the port (implicit on `465`, STARTTLS otherwise); set it for a relay on a non-standard port (e.g. Selectel's `1127` = SSL, `1126` = STARTTLS). |
-| `BACKEND_SMTP_PASSWORD` | — | SMTP password. |
+| `BACKEND_SMTP_USERNAME` | — | SMTP AUTH user; empty relays without authentication. |
-| `BACKEND_SMTP_FROM` | `no-reply@localhost` | Envelope/From address for confirm-codes. |
+| `BACKEND_SMTP_PASSWORD` | — | SMTP AUTH password. |
+| `BACKEND_SMTP_FROM` | `no-reply@localhost` | From address. A deployed contour must use the prod domain (the relay only accepts its verified sender domain). |
+| `BACKEND_PUBLIC_BASE_URL` | — | Canonical public origin (scheme + host) for links in the email. **Required when `BACKEND_SMTP_HOST` is set.** Never derived from a request Host header (anti-injection). |
 | `BACKEND_CONNECTOR_ADDR` | — | the gateway bot-link relay gRPC address for admin-console operator broadcasts. Empty disables broadcasts. |
 | `BACKEND_GUEST_REAP_INTERVAL` | `1h` | How often the abandoned-guest reaper sweeps. |
 | `BACKEND_GUEST_RETENTION` | `720h` | Account age past which a guest with no game seat is deleted. |
@@ -228,7 +232,7 @@ internal/banview/    # gateway active-ban mirror: the console's Active IP bans p
 ```sh
 docker run -d --name scrabble-pg -e POSTGRES_PASSWORD=dev -p 5432:5432 postgres:17-alpine
 # DAWGs: extract the dictionary release artifact (or point at a local scrabble-solver/dawg):
-mkdir -p /tmp/dawg && curl -fsSL https://gitea.iliadenisov.ru/developer/scrabble-dictionary/releases/download/v1.2.1/scrabble-dawg-v1.2.1.tar.gz | tar xz -C /tmp/dawg
+mkdir -p /tmp/dawg && curl -fsSL https://gitea.iliadenisov.ru/developer/scrabble-dictionary/releases/download/v1.3.0/scrabble-dawg-v1.3.0.tar.gz | tar xz -C /tmp/dawg
 BACKEND_POSTGRES_DSN='postgres://postgres:dev@localhost:5432/postgres?search_path=backend&sslmode=disable' \
   BACKEND_DICT_DIR=/tmp/dawg \
   GOPRIVATE='gitea.iliadenisov.ru/*' \

backend/cmd/backend/main.go

@@ -12,6 +12,7 @@ import (
 	"fmt"
 	"log"
 	"os/signal"
+	"strings"
 	"syscall"
 	"time"
 
@@ -20,6 +21,7 @@ import (
 
 	"scrabble/backend/internal/account"
 	"scrabble/backend/internal/accountmerge"
+	"scrabble/backend/internal/adminalert"
 	"scrabble/backend/internal/ads"
 	"scrabble/backend/internal/banview"
 	"scrabble/backend/internal/config"
@@ -33,6 +35,7 @@ import (
 	"scrabble/backend/internal/postgres"
 	"scrabble/backend/internal/pushgrpc"
 	"scrabble/backend/internal/ratewatch"
+	"scrabble/backend/internal/render"
 	"scrabble/backend/internal/robot"
 	"scrabble/backend/internal/server"
 	"scrabble/backend/internal/session"
@@ -43,6 +46,10 @@ import (
 // telemetryShutdownTimeout bounds the OpenTelemetry flush during process exit.
 const telemetryShutdownTimeout = 5 * time.Second
 
+// adminAlertInterval is how often the operator-alert worker checks for new feedback /
+// complaints; a burst within one interval coalesces into a single digest email.
+const adminAlertInterval = 5 * time.Minute
+
 func main() {
 	cfg, err := config.Load()
 	if err != nil {
@@ -161,6 +168,15 @@ func run(ctx context.Context, cfg config.Config, logger *zap.Logger) error {
 		zap.Duration("interval", cfg.GuestReapInterval),
 		zap.Duration("retention", cfg.GuestRetention))
 
+	// Purge the account-deletion legal dossier past its retention TTL: the
+	// retained-identities journal, and the feedback thread + dossier PII of long-deleted
+	// accounts (chat is kept). Checked daily; the TTL is a two-year policy constant.
+	retentionReaper := account.NewRetentionReaper(accounts, account.RetentionTTL, logger)
+	go retentionReaper.Run(ctx, 24*time.Hour)
+	logger.Info("retention reaper started",
+		zap.Duration("interval", 24*time.Hour),
+		zap.Duration("retention", account.RetentionTTL))
+
 	// Re-evaluate moderated-chat write access when a temporary block self-expires:
 	// no operator action fires then, so the sweeper emits the chat-access-changed
 	// event for lapsed blocks and the gateway re-pushes the chat-gate command.
@@ -173,15 +189,20 @@ func run(ctx context.Context, cfg config.Config, logger *zap.Logger) error {
 	// Lobby & social domains. Their REST and stream surface lives in the gateway,
 	// so they are handed to the server (like the route groups) for the handlers.
 	mailer := newMailer(cfg.SMTP, logger)
-	emails := account.NewEmailService(accounts, mailer)
+	emails := account.NewEmailService(accounts, mailer, cfg.PublicBaseURL)
+	// Throttle confirm-code sends per recipient: at most one per minute and five per
+	// rolling hour, guarding against email bombing and the relay's own quota.
+	emails.SetSendLimiter(account.NewSendLimiter(time.Minute, 5))
 	// Account linking & merge: the orchestrator over the account, merge and
 	// session layers. Wired to the /api/v1/user/link REST surface below.
 	links := link.NewService(emails, accounts, accountmerge.NewMerger(db), sessions)
 	socialSvc := social.NewService(social.NewStore(db), accounts, games)
 	socialSvc.SetNotifier(hub)
 	socialSvc.SetMetrics(tel.MeterProvider().Meter("scrabble/backend/social"))
-	// A nudge the recipient answered by moving is marked read on the move path.
+	// A nudge the recipient answered by moving is marked read on the move path; every nudge in a
+	// game is marked read when the game finishes (a stale badge), on any completion path.
 	games.SetNudgeClearer(socialSvc.ClearNudges)
+	games.SetNudgeExpirer(socialSvc.ExpireNudges)
 	// Reap per-game disguised-robot friend requests once their game is long finished
 	// (the robot ignores them; the row only pins the in-game "request sent" state).
 	robotReqReaper := social.NewRobotFriendRequestReaper(socialSvc, logger)
@@ -192,6 +213,18 @@ func run(ctx context.Context, cfg config.Config, logger *zap.Logger) error {
 	feedbackSvc := feedback.NewService(feedback.NewStore(db), accounts)
 	feedbackSvc.SetNotifier(hub)
 
+	// Operator alert emails on new feedback / word complaints, coalesced into one digest
+	// per interval. Inert unless a distinct admin sender and recipient are configured.
+	if cfg.SMTP.AdminFrom != "" && cfg.SMTP.AdminTo != "" {
+		consoleURL := ""
+		if cfg.PublicBaseURL != "" {
+			consoleURL = strings.TrimRight(cfg.PublicBaseURL, "/") + "/_gm"
+		}
+		alerts := adminalert.New(mailer, feedbackSvc, games, cfg.SMTP.AdminFrom, cfg.SMTP.AdminTo, consoleURL, logger)
+		go alerts.Run(ctx, adminAlertInterval)
+		logger.Info("admin alert worker started", zap.Duration("interval", adminAlertInterval))
+	}
+
 	// Robot opponent: provision its durable account pool (a hard startup
 	// dependency, like the dictionaries) and start its move driver. The matchmaker
 	// substitutes a pooled robot for a missing human after the wait window.
@@ -230,6 +263,13 @@ func run(ctx context.Context, cfg config.Config, logger *zap.Logger) error {
 	// block and the banner admin console section.
 	adsSvc := ads.NewService(ads.NewStore(db))
 
+	// The image-render sidecar client for the PNG export artifact; nil (PNG
+	// download answers 404) when BACKEND_RENDERER_URL is unset.
+	var renderer *render.Client
+	if cfg.RendererURL != "" {
+		renderer = render.New(cfg.RendererURL)
+	}
+
 	srv := server.New(cfg.HTTPAddr, server.Deps{
 		Logger:        logger,
 		DB:            db,
@@ -251,6 +291,8 @@ func run(ctx context.Context, cfg config.Config, logger *zap.Logger) error {
 		BanView:       banView,
 		Ads:           adsSvc,
 		Notifier:      hub,
+		ExportSignKey: cfg.ExportSignKey,
+		Renderer:      renderer,
 	})
 	pushSrv := pushgrpc.NewServer(cfg.GRPCAddr, hub, logger)
 

backend/cmd/dictgen/main.go

@@ -0,0 +1,193 @@
+// Command dictgen dumps golden parity vectors from the committed dawg
+// dictionaries so the TypeScript dawg reader can be checked byte-for-byte
+// against the authoritative Go dafsa reader.
+//
+// For each *.dawg file it writes, into the output directory:
+//
+//   - <name>.words.bin — every stored word as alphabet-index bytes, in index
+//     order, framed as [1-byte length][length index bytes]. The word at stream
+//     position k has IndexOfB == k.
+//   - <name>.neg.bin — negative lookups (sequences whose IndexOfB is -1), same
+//     framing, to exercise the not-found path at varying depths.
+//   - <name>.meta.json — NumAdded/NumNodes/NumEdges plus the alphabet size, for
+//     a header-parse sanity cross-check on the TS side.
+//
+// It is a development tool (not built into any service), analogous to
+// cmd/jetgen. Run it from the repository root:
+//
+//	go run ./backend/cmd/dictgen -dawg-dir ../scrabble-solver/dawg -out <dir>
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	dawg "github.com/iliadenisov/dafsa"
+)
+
+// meta is the per-dictionary sanity payload cross-checked by the TS reader.
+type meta struct {
+	NumAdded int `json:"numAdded"`
+	NumNodes int `json:"numNodes"`
+	NumEdges int `json:"numEdges"`
+	Alphabet int `json:"alphabet"`
+}
+
+func main() {
+	dawgDir := flag.String("dawg-dir", "../scrabble-solver/dawg", "directory holding the .dawg files")
+	outDir := flag.String("out", "", "output directory for the golden files (required)")
+	negCount := flag.Int("neg", 20000, "number of negative lookups to emit per dictionary")
+	flag.Parse()
+
+	if *outDir == "" {
+		fail("-out is required")
+	}
+	if err := os.MkdirAll(*outDir, 0o755); err != nil {
+		fail("mkdir out: %v", err)
+	}
+
+	files, err := filepath.Glob(filepath.Join(*dawgDir, "*.dawg"))
+	if err != nil {
+		fail("glob: %v", err)
+	}
+	sort.Strings(files)
+	if len(files) == 0 {
+		fail("no .dawg files in %s", *dawgDir)
+	}
+
+	for _, f := range files {
+		if err := process(f, *outDir, *negCount); err != nil {
+			fail("%s: %v", filepath.Base(f), err)
+		}
+	}
+}
+
+// process emits the golden files for a single dawg dictionary.
+func process(path, outDir string, negCount int) error {
+	name := strings.TrimSuffix(filepath.Base(path), ".dawg")
+
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	finder, err := dawg.Read(bytes.NewReader(data), 0)
+	if err != nil {
+		return fmt.Errorf("read dawg: %w", err)
+	}
+	defer finder.Close()
+
+	// Stream every stored word in index order; keep a decimated sample and the
+	// maximum alphabet index for negative generation.
+	wf, err := os.Create(filepath.Join(outDir, name+".words.bin"))
+	if err != nil {
+		return err
+	}
+	bw := bufio.NewWriter(wf)
+
+	var (
+		count  int
+		maxIx  byte
+		sample [][]byte
+	)
+	finder.EnumerateB(func(index int, word []byte, final bool) int {
+		if !final {
+			return 0 // Continue
+		}
+		if index != count {
+			panic(fmt.Sprintf("%s: enumerate index gap: got %d want %d", name, index, count))
+		}
+		writeWord(bw, word)
+		for _, b := range word {
+			if b > maxIx {
+				maxIx = b
+			}
+		}
+		if count%4 == 0 && len(sample) < 60000 {
+			sample = append(sample, append([]byte(nil), word...))
+		}
+		count++
+		return 0 // Continue
+	})
+	if err := bw.Flush(); err != nil {
+		return err
+	}
+	if err := wf.Close(); err != nil {
+		return err
+	}
+	if count != finder.NumAdded() {
+		return fmt.Errorf("word count %d != NumAdded %d", count, finder.NumAdded())
+	}
+
+	alphabet := int(maxIx) + 1
+
+	// Negatives: mutate sampled real words and keep the ones the reader rejects.
+	nf, err := os.Create(filepath.Join(outDir, name+".neg.bin"))
+	if err != nil {
+		return err
+	}
+	nbw := bufio.NewWriter(nf)
+	rng := rand.New(rand.NewSource(1))
+	neg := 0
+	for neg < negCount && len(sample) > 0 {
+		base := sample[rng.Intn(len(sample))]
+		cand := append([]byte(nil), base...)
+		switch rng.Intn(3) {
+		case 0: // extend by one index
+			cand = append(cand, byte(rng.Intn(alphabet)))
+		case 1: // flip one index
+			if len(cand) > 0 {
+				cand[rng.Intn(len(cand))] = byte(rng.Intn(alphabet))
+			}
+		case 2: // drop the tail and flip the new last index
+			if len(cand) > 1 {
+				cand = cand[:len(cand)-1]
+				cand[len(cand)-1] = byte(rng.Intn(alphabet))
+			}
+		}
+		if finder.IndexOfB(cand) == -1 {
+			writeWord(nbw, cand)
+			neg++
+		}
+	}
+	if err := nbw.Flush(); err != nil {
+		return err
+	}
+	if err := nf.Close(); err != nil {
+		return err
+	}
+
+	m := meta{NumAdded: finder.NumAdded(), NumNodes: finder.NumNodes(), NumEdges: finder.NumEdges(), Alphabet: alphabet}
+	mb, err := json.MarshalIndent(m, "", "  ")
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(filepath.Join(outDir, name+".meta.json"), mb, 0o644); err != nil {
+		return err
+	}
+
+	fmt.Printf("%-12s words=%d negatives=%d alphabet=%d nodes=%d edges=%d\n",
+		name, count, neg, alphabet, finder.NumNodes(), finder.NumEdges())
+	return nil
+}
+
+// writeWord frames one index-byte word as [length][bytes].
+func writeWord(w *bufio.Writer, word []byte) {
+	if len(word) > 255 {
+		panic(fmt.Sprintf("word too long to frame: %d", len(word)))
+	}
+	w.WriteByte(byte(len(word)))
+	w.Write(word)
+}
+
+func fail(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, "dictgen: "+format+"\n", args...)
+	os.Exit(1)
+}

backend/cmd/validategen/main.go

@@ -0,0 +1,486 @@
+// Command validategen produces golden conformance fixtures for the TypeScript
+// move validator (ui/src/lib/dict/validate.ts). For each variant it self-plays
+// greedy games with the authoritative scrabble-solver engine to build realistic
+// board positions, then records a battery of candidate plays — the engine's own
+// top move, letter-mutated variants, random scatters and (on the empty board) an
+// off-centre translation — each paired with the ground-truth result of
+// ValidatePlayOpts (legal, score, the words formed). The TS conformance test
+// replays these and must agree exactly.
+//
+// It is a development tool (not built into any service), analogous to
+// cmd/dictgen. Run it from the repository root:
+//
+//	go run ./backend/cmd/validategen -dawg-dir ../scrabble-solver/dawg -out <dir>
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"math/rand"
+	"os"
+	"path/filepath"
+
+	"gitea.iliadenisov.ru/developer/scrabble-solver/board"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rack"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/selfplay"
+	dawg "github.com/iliadenisov/dafsa"
+)
+
+// blankTile marks a blank tile in a drawn hand (matches selfplay).
+const blankTile byte = 0xff
+
+// variantSpec pairs a variant label with its ruleset and dawg file.
+type variantSpec struct {
+	name  string
+	rules *rules.Ruleset
+	dawg  string
+}
+
+// cell is an occupied board square or a placement (alphabet-index letter).
+type cell struct {
+	R, C, Letter int
+	Blank        bool
+}
+
+// word mirrors scrabble.Word in index space.
+type word struct {
+	Row, Col, Dir int
+	Letters       []int
+	Blanks        []bool
+	Score         int
+}
+
+// fixture is one candidate play with the engine's ground-truth verdict.
+type fixture struct {
+	Board            int    `json:"board"` // index into the boards list
+	Dir              int    `json:"dir"`
+	IgnoreCrossWords bool   `json:"ignoreCrossWords"`
+	Tiles            []cell `json:"tiles"`
+	Legal            bool   `json:"legal"`
+	Score            int    `json:"score"`
+	Bonus            int    `json:"bonus"`
+	Main             *word  `json:"main,omitempty"`
+	Cross            []word `json:"cross,omitempty"`
+}
+
+// alphaEntry mirrors one row of the per-variant alphabet table the server sends the
+// client (index, concrete letter as the ruleset emits it, tile value), so the adapter
+// cross-test can drive the letter-space client path exactly as production does.
+type alphaEntry struct {
+	Index  int    `json:"index"`
+	Letter string `json:"letter"`
+	Value  int    `json:"value"`
+}
+
+// variantFile is the whole conformance payload for one variant.
+type variantFile struct {
+	Variant  string       `json:"variant"`
+	Rows     int          `json:"rows"`
+	Cols     int          `json:"cols"`
+	Center   int          `json:"center"`
+	RackSize int          `json:"rackSize"`
+	Bingo    int          `json:"bingo"`
+	Values   []int        `json:"values"`
+	Premiums []int        `json:"premiums"` // row-major rules.Premium codes
+	Alphabet []alphaEntry `json:"alphabet"`
+	Boards   [][]cell     `json:"boards"`
+	Fixtures []fixture    `json:"fixtures"`
+}
+
+func main() {
+	dawgDir := flag.String("dawg-dir", "../scrabble-solver/dawg", "directory holding the .dawg files")
+	outDir := flag.String("out", "", "output directory for the fixture files (required)")
+	games := flag.Int("games", 6, "self-play games per (variant, rule)")
+	plies := flag.Int("plies", 40, "maximum plies captured per game")
+	flag.Parse()
+	if *outDir == "" {
+		fail("-out is required")
+	}
+	if err := os.MkdirAll(*outDir, 0o755); err != nil {
+		fail("mkdir out: %v", err)
+	}
+
+	specs := []variantSpec{
+		{"scrabble_en", rules.English(), "en_sowpods.dawg"},
+		{"scrabble_ru", rules.RussianScrabble(), "ru_scrabble.dawg"},
+		{"erudit_ru", rules.Erudit(), "ru_erudit.dawg"},
+	}
+	for _, sp := range specs {
+		if err := generate(sp, *dawgDir, *outDir, *games, *plies); err != nil {
+			fail("%s: %v", sp.name, err)
+		}
+	}
+}
+
+func generate(sp variantSpec, dawgDir, outDir string, games, plies int) error {
+	data, err := os.ReadFile(filepath.Join(dawgDir, sp.dawg))
+	if err != nil {
+		return err
+	}
+	finder, err := dawg.Read(bytes.NewReader(data), 0)
+	if err != nil {
+		return fmt.Errorf("read dawg: %w", err)
+	}
+	defer finder.Close()
+
+	rs := sp.rules
+	solver := scrabble.NewSolver(rs, finder)
+
+	out := variantFile{
+		Variant: sp.name, Rows: rs.Rows, Cols: rs.Cols, Center: rs.Center,
+		RackSize: rs.RackSize, Bingo: rs.Bingo, Values: rs.Values,
+		Premiums: premiumCodes(rs), Alphabet: alphabetOf(rs),
+	}
+
+	// Capture under both the standard rule and the single-word rule, building the
+	// board with the same rule so positions are reachable under it.
+	for _, ignore := range []bool{false, true} {
+		opts := scrabble.PlayOptions{IgnoreCrossWords: ignore}
+		for g := range games {
+			seed := int64(g*1000) + boolseed(ignore) + variantSeed(sp.name)
+			playAndCapture(&out, rs, solver, opts, seed, plies)
+		}
+	}
+
+	b, err := json.Marshal(&out)
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(filepath.Join(outDir, sp.name+".fixtures.json"), b, 0o644); err != nil {
+		return err
+	}
+	fmt.Printf("%-12s boards=%d fixtures=%d\n", sp.name, len(out.Boards), len(out.Fixtures))
+	return nil
+}
+
+// playAndCapture greedily self-plays one game, recording candidate plays against
+// each board position along the way.
+func playAndCapture(out *variantFile, rs *rules.Ruleset, solver *scrabble.Solver, opts scrabble.PlayOptions, seed int64, plies int) {
+	rng := rand.New(rand.NewSource(seed))
+	bag := selfplay.NewBag(rs, seed)
+	b := board.New(rs.Rows, rs.Cols)
+	hands := [2][]byte{bag.Draw(rs.RackSize), bag.Draw(rs.RackSize)}
+
+	passes := 0
+	for turn := range plies {
+		p := turn % 2
+		rk := rackOf(hands[p], rs.Size())
+		moves := solver.GenerateMovesOpts(b, rk, scrabble.Both, opts)
+		if len(moves) == 0 {
+			if passes++; passes >= 4 {
+				break
+			}
+			continue
+		}
+		passes = 0
+		top := moves[0]
+
+		boardIdx := len(out.Boards)
+		out.Boards = append(out.Boards, boardCells(b))
+		captureCandidates(out, rs, solver, opts, b, boardIdx, top, rng)
+
+		scrabble.Apply(b, top)
+		hands[p] = removeUsed(hands[p], top)
+		if need := rs.RackSize - len(hands[p]); need > 0 {
+			hands[p] = append(hands[p], bag.Draw(need)...)
+		}
+		if len(hands[p]) == 0 && bag.Len() == 0 {
+			break
+		}
+	}
+}
+
+// captureCandidates records the engine's top move plus derived candidates for one
+// board, each with its ValidatePlayOpts verdict.
+func captureCandidates(out *variantFile, rs *rules.Ruleset, solver *scrabble.Solver, opts scrabble.PlayOptions, b *board.Board, boardIdx int, top scrabble.Move, rng *rand.Rand) {
+	size := rs.Size()
+	record := func(tiles []scrabble.Placement) {
+		if len(tiles) == 0 {
+			return
+		}
+		out.Fixtures = append(out.Fixtures, makeFixture(solver, opts, b, boardIdx, tiles))
+	}
+
+	// The engine's own top move (legal).
+	record(top.Tiles)
+
+	// Letter-mutated variants: usually reject on the dictionary, occasionally form
+	// a different legal word.
+	for range 3 {
+		mut := clonePlacements(top.Tiles)
+		i := rng.Intn(len(mut))
+		mut[i].Letter = byte((int(mut[i].Letter) + 1 + rng.Intn(size-1)) % size)
+		record(mut)
+	}
+
+	// Random scatters: exercise geometry, dictionary and connectivity paths.
+	for range 3 {
+		record(randomScatter(b, size, 2+rng.Intn(4), rng))
+	}
+
+	// Single tiles abutting the board exercise the direction inference — a single
+	// tile is ambiguous, its orientation resolved from which axis it extends.
+	for range 3 {
+		if t, ok := randomAdjacentSingle(b, size, rng); ok {
+			record([]scrabble.Placement{t})
+		}
+	}
+
+	// On the empty board, an off-centre translation of the first move exercises the
+	// first-move centre rule.
+	if b.IsEmpty() {
+		shifted := clonePlacements(top.Tiles)
+		ok := true
+		for i := range shifted {
+			shifted[i].Row++
+			shifted[i].Col++
+			if !b.InBounds(shifted[i].Row, shifted[i].Col) {
+				ok = false
+				break
+			}
+		}
+		if ok {
+			record(shifted)
+		}
+	}
+}
+
+// makeFixture validates a candidate against board b and serializes it with its
+// ground truth. Word breakdown is recorded only for legal plays (the TS test
+// checks words only then); an illegal play records legal=false alone.
+func makeFixture(solver *scrabble.Solver, opts scrabble.PlayOptions, b *board.Board, boardIdx int, tiles []scrabble.Placement) fixture {
+	// Infer the orientation exactly as the backend evaluate does (dir-less), so the
+	// fixture matches the real eval path and pins the client's ported inference.
+	dir := playDirectionMirror(solver, b, tiles, opts)
+	fx := fixture{
+		Board:            boardIdx,
+		Dir:              int(dir),
+		IgnoreCrossWords: opts.IgnoreCrossWords,
+		Tiles:            placementCells(tiles),
+	}
+	m, err := solver.ValidatePlayOpts(b, dir, tiles, opts)
+	if err == nil {
+		fx.Legal = true
+		fx.Score = m.Score
+		fx.Bonus = m.Bonus
+		fx.Main = toWord(m.Main)
+		for _, cw := range m.Cross {
+			fx.Cross = append(fx.Cross, *toWord(cw))
+		}
+	}
+	return fx
+}
+
+func placementCells(ts []scrabble.Placement) []cell {
+	cs := make([]cell, len(ts))
+	for i, t := range ts {
+		cs[i] = cell{R: t.Row, C: t.Col, Letter: int(t.Letter), Blank: t.Blank}
+	}
+	return cs
+}
+
+func toWord(w scrabble.Word) *word {
+	letters := make([]int, len(w.Letters))
+	for i, l := range w.Letters {
+		letters[i] = int(l)
+	}
+	return &word{
+		Row: w.Row, Col: w.Col, Dir: int(w.Dir),
+		Letters: letters, Blanks: append([]bool(nil), w.Blanks...), Score: w.Score,
+	}
+}
+
+func alphabetOf(rs *rules.Ruleset) []alphaEntry {
+	n := rs.Alphabet.Size()
+	out := make([]alphaEntry, n)
+	for i := range n {
+		ch, _ := rs.Alphabet.Character(byte(i))
+		out[i] = alphaEntry{Index: i, Letter: ch, Value: rs.Values[i]}
+	}
+	return out
+}
+
+func premiumCodes(rs *rules.Ruleset) []int {
+	codes := make([]int, rs.Rows*rs.Cols)
+	for i := range codes {
+		codes[i] = int(rs.PremiumAt(i))
+	}
+	return codes
+}
+
+func boardCells(b *board.Board) []cell {
+	var cs []cell
+	for r := 0; r < b.Rows(); r++ {
+		for c := 0; c < b.Cols(); c++ {
+			if b.Filled(r, c) {
+				v := b.At(r, c)
+				cs = append(cs, cell{R: r, C: c, Letter: int(v&0x3f) - 1, Blank: v&0x80 != 0})
+			}
+		}
+	}
+	return cs
+}
+
+func clonePlacements(ts []scrabble.Placement) []scrabble.Placement {
+	return append([]scrabble.Placement(nil), ts...)
+}
+
+// randomScatter picks n distinct empty in-bounds squares with random letters.
+func randomScatter(b *board.Board, size, n int, rng *rand.Rand) []scrabble.Placement {
+	seen := map[[2]int]bool{}
+	var ts []scrabble.Placement
+	for tries := 0; tries < n*20 && len(ts) < n; tries++ {
+		r := rng.Intn(b.Rows())
+		c := rng.Intn(b.Cols())
+		if seen[[2]int{r, c}] || b.Filled(r, c) {
+			continue
+		}
+		seen[[2]int{r, c}] = true
+		ts = append(ts, scrabble.Placement{Row: r, Col: c, Letter: byte(rng.Intn(size)), Blank: rng.Intn(10) == 0})
+	}
+	return ts
+}
+
+// randomAdjacentSingle picks a random empty in-bounds square abutting at least one
+// filled square, with a random letter — a single-tile play whose orientation the
+// inference must resolve. It returns ok=false on an empty board.
+func randomAdjacentSingle(b *board.Board, size int, rng *rand.Rand) (scrabble.Placement, bool) {
+	var cands [][2]int
+	for r := 0; r < b.Rows(); r++ {
+		for c := 0; c < b.Cols(); c++ {
+			if b.Filled(r, c) {
+				continue
+			}
+			if b.Filled(r-1, c) || b.Filled(r+1, c) || b.Filled(r, c-1) || b.Filled(r, c+1) {
+				cands = append(cands, [2]int{r, c})
+			}
+		}
+	}
+	if len(cands) == 0 {
+		return scrabble.Placement{}, false
+	}
+	rc := cands[rng.Intn(len(cands))]
+	return scrabble.Placement{Row: rc[0], Col: rc[1], Letter: byte(rng.Intn(size)), Blank: rng.Intn(10) == 0}, true
+}
+
+// playDirectionMirror mirrors engine (*Game).playDirection: the geometric
+// resolution, except a single tile under the single-word rule tries both
+// orientations through the solver and keeps the higher-scoring legal one (H wins
+// ties). It reproduces the orientation the backend evaluate infers.
+func playDirectionMirror(solver *scrabble.Solver, b *board.Board, placements []scrabble.Placement, opts scrabble.PlayOptions) scrabble.Direction {
+	geo := resolveDirectionMirror(b, placements)
+	if len(placements) != 1 || !opts.IgnoreCrossWords {
+		return geo
+	}
+	best, found, bestScore := geo, false, 0
+	for _, dir := range [...]scrabble.Direction{scrabble.Horizontal, scrabble.Vertical} {
+		m, err := solver.ValidatePlayOpts(b, dir, placements, opts)
+		if err != nil {
+			continue
+		}
+		if !found || m.Score > bestScore {
+			best, found, bestScore = dir, true, m.Score
+		}
+	}
+	return best
+}
+
+// resolveDirectionMirror mirrors engine.resolveDirection.
+func resolveDirectionMirror(b *board.Board, placements []scrabble.Placement) scrabble.Direction {
+	if len(placements) >= 2 {
+		row := placements[0].Row
+		for _, p := range placements[1:] {
+			if p.Row != row {
+				return scrabble.Vertical
+			}
+		}
+		return scrabble.Horizontal
+	}
+	if len(placements) == 1 {
+		p := placements[0]
+		h := runLengthMirror(b, p.Row, p.Col, scrabble.Horizontal)
+		v := runLengthMirror(b, p.Row, p.Col, scrabble.Vertical)
+		if v >= 2 && v > h {
+			return scrabble.Vertical
+		}
+		if h >= 2 {
+			return scrabble.Horizontal
+		}
+		if v >= 2 {
+			return scrabble.Vertical
+		}
+	}
+	return scrabble.Horizontal
+}
+
+// runLengthMirror mirrors engine.runLength.
+func runLengthMirror(b *board.Board, row, col int, dir scrabble.Direction) int {
+	dr, dc := 0, 1
+	if dir == scrabble.Vertical {
+		dr, dc = 1, 0
+	}
+	n := 1
+	for r, c := row-dr, col-dc; b.Filled(r, c); r, c = r-dr, c-dc {
+		n++
+	}
+	for r, c := row+dr, col+dc; b.Filled(r, c); r, c = r+dr, c+dc {
+		n++
+	}
+	return n
+}
+
+// rackOf builds a generation rack from a hand of tiles (reimplemented from the
+// unexported selfplay helper).
+func rackOf(tiles []byte, size int) rack.Rack {
+	r := rack.New(size)
+	for _, t := range tiles {
+		if t == blankTile {
+			r.AddBlank()
+		} else {
+			r.Add(t)
+		}
+	}
+	return r
+}
+
+// removeUsed returns the hand with the tiles consumed by m removed.
+func removeUsed(tiles []byte, m scrabble.Move) []byte {
+	out := append([]byte(nil), tiles...)
+	for _, p := range m.Tiles {
+		want := p.Letter
+		if p.Blank {
+			want = blankTile
+		}
+		for i, t := range out {
+			if t == want {
+				out = append(out[:i], out[i+1:]...)
+				break
+			}
+		}
+	}
+	return out
+}
+
+func boolseed(b bool) int64 {
+	if b {
+		return 500000
+	}
+	return 0
+}
+
+func variantSeed(name string) int64 {
+	var s int64
+	for _, r := range name {
+		s = s*131 + int64(r)
+	}
+	return s
+}
+
+func fail(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, "validategen: "+format+"\n", args...)
+	os.Exit(1)
+}

backend/go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/pressly/goose/v3 v3.27.1
 	github.com/testcontainers/testcontainers-go v0.42.0
 	github.com/testcontainers/testcontainers-go/modules/postgres v0.42.0
+	github.com/wneessen/go-mail v0.7.3
 	go.opentelemetry.io/otel v1.43.0
 	go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v1.43.0
 	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.43.0
@@ -109,7 +110,7 @@ require (
 	golang.org/x/net v0.53.0 // indirect
 	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.43.0 // indirect
-	golang.org/x/text v0.36.0 // indirect
+	golang.org/x/text v0.37.0 // indirect
 	google.golang.org/grpc v1.80.0
 	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

backend/go.sum

@@ -279,6 +279,8 @@ github.com/twitchyliquid64/golang-asm v0.15.1 h1:SU5vSMR7hnwNxj24w34ZyCi/FmDZTkS
 github.com/twitchyliquid64/golang-asm v0.15.1/go.mod h1:a1lVb/DtPvCB8fslRZhAngC2+aY1QWCk3Cedj/Gdt08=
 github.com/ugorji/go/codec v1.3.1 h1:waO7eEiFDwidsBN6agj1vJQ4AG7lh2yqXyOXqhgQuyY=
 github.com/ugorji/go/codec v1.3.1/go.mod h1:pRBVtBSKl77K30Bv8R2P+cLSGaTtex6fsA2Wjqmfxj4=
+github.com/wneessen/go-mail v0.7.3 h1:g3DravXC5SMlVdboFrQA8Jx95A8sOzoBeS5F+vzNRK0=
+github.com/wneessen/go-mail v0.7.3/go.mod h1:QGhBX0yNbc1J+Mkjcu7z2rpj4B4l+BmDY8gYznPC9sk=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 github.com/yusufpapurcu/wmi v1.2.4 h1:zFUKzehAFReQwLys1b/iSMl+JQGSCSjtVqQn9bBrPo0=
 github.com/yusufpapurcu/wmi v1.2.4/go.mod h1:SBZ9tNy3G9/m5Oi98Zks0QjeHVDvuK0qfxQmPyzfmi0=
@@ -400,6 +402,8 @@ golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 golang.org/x/text v0.36.0 h1:JfKh3XmcRPqZPKevfXVpI1wXPTqbkE5f7JA92a55Yxg=
 golang.org/x/text v0.36.0/go.mod h1:NIdBknypM8iqVmPiuco0Dh6P5Jcdk8lJL0CUebqK164=
+golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
+golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190425163242-31fd60d6bfdc/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=

backend/internal/account/account.go

@@ -22,12 +22,13 @@ import (
 	"scrabble/backend/internal/postgres/jet/backend/table"
 )
 
-// Identity kinds recognised by the backend. Email is modelled as an identity
+// Identity kinds recognised by the backend. Telegram and VK are platform identities,
-// alongside platform identities; its confirmed flag is driven by the email
+// auto-confirmed on first contact. Email is modelled as an identity alongside them; its
-// confirm-code flow. Robot is a synthetic kind: each pooled
+// confirmed flag is driven by the email confirm-code flow. Robot is a synthetic kind:
-// robot opponent is a durable account bound to one robot identity.
+// each pooled robot opponent is a durable account bound to one robot identity.
 const (
 	KindTelegram = "telegram"
+	KindVK       = "vk"
 	KindEmail    = "email"
 	KindRobot    = "robot"
 )
@@ -119,6 +120,47 @@ func (s *Store) ProvisionByIdentity(ctx context.Context, kind, externalID string
 	return s.provision(ctx, kind, externalID, provisionSeed{})
 }
 
+// ProvisionEmail returns the account owning the email identity externalID, creating
+// it on first contact with browserTZ — the client's detected "±HH:MM" UTC offset —
+// seeded into its time zone, language seeded from the client's UI language, and its
+// display name seeded from the email's local part (so it is not left nameless). Like
+// ProvisionByIdentity it is race-safe and leaves an existing account untouched, so a
+// returning user's saved zone, language and name are never overwritten. The email account is
+// created here (the code-request step), not at the later login, so this is where its
+// zone and language are seeded. It is created flagged is_guest with an unconfirmed
+// email identity: an abandoned, never-confirmed login is then reaped like any guest,
+// freeing the reserved address, and confirming the code clears the guest flag.
+func (s *Store) ProvisionEmail(ctx context.Context, externalID, browserTZ, language string) (Account, error) {
+	return s.provision(ctx, KindEmail, externalID, provisionSeed{
+		displayName:       emailDisplayName(externalID),
+		timeZone:          seedZone(browserTZ),
+		preferredLanguage: supportedLanguage(language),
+		isGuest:           true,
+	})
+}
+
+// emailDisplayName derives a display name from an email address — the local part
+// before '@', trimmed and capped to the column width — so a new email account is not
+// left nameless. It is only the first-contact seed; the user can rename it later.
+func emailDisplayName(email string) string {
+	local, _, _ := strings.Cut(email, "@")
+	local = strings.TrimSpace(local)
+	if r := []rune(local); len(r) > maxDisplayName {
+		local = strings.TrimRight(string(r[:maxDisplayName]), " ")
+	}
+	return local
+}
+
+// supportedLanguage returns code normalised to a supported UI language ("en" or
+// "ru"), or "" when it maps to neither, so a new account keeps the 'en' default. It
+// accepts region-tagged codes ("ru-RU").
+func supportedLanguage(code string) string {
+	if lang, _, _ := strings.Cut(strings.ToLower(strings.TrimSpace(code)), "-"); lang == "en" || lang == "ru" {
+		return lang
+	}
+	return ""
+}
+
 // ProvisionRobot provisions (or finds) the durable account backing a robot pool
 // member: a KindRobot identity carrying displayName, with chat blocked but friend
 // requests NOT blocked — a request to a robot is accepted as pending and, since the
@@ -160,7 +202,7 @@ func (s *Store) ProvisionRobot(ctx context.Context, externalID, displayName stri
 // is never overwritten. The created flag lets the auth handler re-evaluate moderated-
 // chat write access on first registration — the path of a user who joined the chat
 // before registering, whom no chat_member event covers.
-func (s *Store) ProvisionTelegram(ctx context.Context, externalID, languageCode, username, firstName string) (Account, bool, error) {
+func (s *Store) ProvisionTelegram(ctx context.Context, externalID, languageCode, username, firstName, browserTZ string) (Account, bool, error) {
 	// Pre-check whether the identity already exists so the caller can act on first
 	// contact. A race with a concurrent create only over- or under-reports created for
 	// that one call, which the idempotent chat-access re-evaluation tolerates.
@@ -169,7 +211,31 @@ func (s *Store) ProvisionTelegram(ctx context.Context, externalID, languageCode,
 	if err != nil && !created {
 		return Account{}, false, err
 	}
-	acc, err := s.provision(ctx, KindTelegram, externalID, telegramSeed(languageCode, username, firstName))
+	seed := telegramSeed(languageCode, username, firstName)
+	seed.timeZone = seedZone(browserTZ)
+	acc, err := s.provision(ctx, KindTelegram, externalID, seed)
+	return acc, created, err
+}
+
+// ProvisionVK provisions (or finds) the account bound to a VK identity, reporting
+// whether this call created it (first contact). On first contact only, it seeds the new
+// account's preferred language from the VK languageCode (vk_language, when it maps to a
+// supported language) and its display name sanitized from displayName — the name read
+// client-side via VKWebAppGetUserInfo, since VK omits it from the signed launch params —
+// falling back to a generated placeholder when it yields no letters; an already-existing
+// account is returned unchanged, so a later profile edit is never overwritten.
+func (s *Store) ProvisionVK(ctx context.Context, externalID, languageCode, displayName, browserTZ string) (Account, bool, error) {
+	// Pre-check whether the identity already exists so the caller can act on first
+	// contact (mirrors ProvisionTelegram); a create race only mis-reports created for
+	// that one call.
+	_, err := s.findByIdentity(ctx, KindVK, externalID)
+	created := errors.Is(err, ErrNotFound)
+	if err != nil && !created {
+		return Account{}, false, err
+	}
+	seed := vkSeed(languageCode, displayName)
+	seed.timeZone = seedZone(browserTZ)
+	acc, err := s.provision(ctx, KindVK, externalID, seed)
 	return acc, created, err
 }
 
@@ -197,12 +263,29 @@ func (s *Store) provision(ctx context.Context, kind, externalID string, seed pro
 }
 
 // provisionSeed carries the optional create-time profile seed for a brand-new
-// account (Telegram first contact). Empty fields fall back to the accounts table
+// account (first contact). Empty fields fall back to the accounts table defaults,
-// defaults, so an unknown language keeps the 'en' default and an empty name keeps
+// so an unknown language keeps the 'en' default, an empty name keeps the ” default
-// the ” default.
+// and an empty time zone keeps the 'UTC' default.
 type provisionSeed struct {
 	preferredLanguage string
 	displayName       string
+	timeZone          string
+	// isGuest creates the account flagged is_guest. It is set for an email-login
+	// account, which stays a guest until the address is confirmed (so an abandoned,
+	// never-confirmed login is reaped and its address freed); confirming clears the
+	// flag. Platform identities (telegram/vk) are durable from creation.
+	isGuest bool
+}
+
+// seedZone returns browserTZ when it is a well-formed zone to persist at account
+// creation (a "±HH:MM" offset or a loadable IANA name), else "" so the new account
+// falls back to the accounts table's 'UTC' default. The client reports the device's
+// detected offset deterministically; a bad value is dropped rather than guessed at.
+func seedZone(browserTZ string) string {
+	if validZone(browserTZ) {
+		return browserTZ
+	}
+	return ""
 }
 
 // telegramSeed derives the create-time seed from Telegram launch fields: a
@@ -234,6 +317,24 @@ func telegramSeed(languageCode, username, firstName string) provisionSeed {
 	return seed
 }
 
+// vkSeed derives the create-time seed from VK launch fields: a supported preferred
+// language from languageCode (vk_language, normally a 2-letter code) and a display name
+// from displayName (sanitized to the editable format), falling back to a generated
+// placeholder in the seeded language when the name yields no usable letters. Unlike
+// telegramSeed there is no @username fallback — VK provides only the name.
+func vkSeed(languageCode, displayName string) provisionSeed {
+	var seed provisionSeed
+	if lang, _, _ := strings.Cut(strings.ToLower(strings.TrimSpace(languageCode)), "-"); lang == "en" || lang == "ru" {
+		seed.preferredLanguage = lang
+	}
+	name := sanitizeDisplayName(displayName)
+	if name == "" {
+		name = placeholderDisplayName(seed.preferredLanguage)
+	}
+	seed.displayName = name
+	return seed
+}
+
 // GetByID loads the account identified by id, or ErrNotFound when it is absent.
 func (s *Store) GetByID(ctx context.Context, id uuid.UUID) (Account, error) {
 	stmt := postgres.SELECT(table.Accounts.AllColumns).
@@ -368,16 +469,22 @@ func (s *Store) create(ctx context.Context, kind, externalID string, seed provis
 
 	var created Account
 	err = withTx(ctx, s.db, func(tx *sql.Tx) error {
-		// Seed the new row's display name and language (Telegram first contact); an
+		// Seed the new row's display name, language and time zone (first contact); an
-		// empty seed reproduces the table defaults ('' and 'en') the other callers
+		// empty seed reproduces the table defaults ('', 'en' and 'UTC') the other callers
-		// relied on, so their behaviour is unchanged.
+		// relied on, so their behaviour is unchanged. time_zone is written explicitly (the
+		// detected offset, or 'UTC' equal to the column default) so a seeded zone lands at
+		// creation while an unseeded one stays UTC.
 		lang := seed.preferredLanguage
 		if lang == "" {
 			lang = "en"
 		}
+		tz := seed.timeZone
+		if tz == "" {
+			tz = "UTC"
+		}
 		insertAccount := table.Accounts.
-			INSERT(table.Accounts.AccountID, table.Accounts.DisplayName, table.Accounts.PreferredLanguage).
+			INSERT(table.Accounts.AccountID, table.Accounts.DisplayName, table.Accounts.PreferredLanguage, table.Accounts.TimeZone, table.Accounts.IsGuest).
-			VALUES(accountID, seed.displayName, lang).
+			VALUES(accountID, seed.displayName, lang, tz, seed.isGuest).
 			RETURNING(table.Accounts.AllColumns)
 
 		var row model.Accounts
@@ -391,7 +498,7 @@ func (s *Store) create(ctx context.Context, kind, externalID string, seed provis
 			table.Identities.Kind,
 			table.Identities.ExternalID,
 			table.Identities.Confirmed,
-		).VALUES(identityID, accountID, kind, externalID, kind == KindTelegram)
+		).VALUES(identityID, accountID, kind, externalID, kind == KindTelegram || kind == KindVK)
 		if _, err := insertIdentity.ExecContext(ctx, tx); err != nil {
 			return err
 		}
@@ -416,15 +523,21 @@ const guestDisplayName = "Guest"
 // ProvisionGuest creates a fresh ephemeral guest account: a durable row carrying
 // no identity, flagged is_guest, so it can hold a session and a game seat (both
 // foreign-key the accounts table) while being excluded from statistics, friends
-// and history. Guests are not reused — each bootstrap mints a new account.
+// and history. Guests are not reused — each bootstrap mints a new account. browserTZ
-func (s *Store) ProvisionGuest(ctx context.Context) (Account, error) {
+// (the client's detected "±HH:MM" UTC offset) seeds the guest's time zone, falling
+// back to the 'UTC' default when empty or malformed.
+func (s *Store) ProvisionGuest(ctx context.Context, browserTZ string) (Account, error) {
 	accountID, err := uuid.NewV7()
 	if err != nil {
 		return Account{}, fmt.Errorf("account: new guest id: %w", err)
 	}
+	tz := seedZone(browserTZ)
+	if tz == "" {
+		tz = "UTC"
+	}
 	stmt := table.Accounts.
-		INSERT(table.Accounts.AccountID, table.Accounts.DisplayName, table.Accounts.IsGuest).
+		INSERT(table.Accounts.AccountID, table.Accounts.DisplayName, table.Accounts.IsGuest, table.Accounts.TimeZone).
-		VALUES(accountID, guestDisplayName, true).
+		VALUES(accountID, guestDisplayName, true, tz).
 		RETURNING(table.Accounts.AllColumns)
 
 	var row model.Accounts

backend/internal/account/email.go

@@ -5,6 +5,7 @@ import (
 	crand "crypto/rand"
 	"crypto/sha256"
 	"database/sql"
+	"encoding/base64"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -26,6 +27,22 @@ const (
 	emailCodeTTL = 15 * time.Minute
 	// emailCodeMaxAttempts caps wrong-code submissions before a code is dead.
 	emailCodeMaxAttempts = 5
+	// linkTokenBytes is the entropy of a confirm deeplink token: 256 bits.
+	linkTokenBytes = 32
+	// emailConfirmPath is the SPA route the one-tap confirm deeplink opens (the token
+	// is appended). The SPA is served under /app/ behind a hash router.
+	emailConfirmPath = "/app/#/confirm/"
+)
+
+// Confirmation purposes recorded on a pending confirm-code row. They select what
+// verifying the code or the deeplink token does: sign in (login), link/confirm the
+// address on the current account (link), or replace the account's confirmed email with
+// a new address (change). Account deletion adds a further purpose in a later stage.
+const (
+	purposeLogin  = "login"
+	purposeLink   = "link"
+	purposeChange = "change"
+	purposeDelete = "delete"
 )
 
 // Errors returned by the email confirm-code flow.
@@ -46,6 +63,12 @@ var (
 	ErrTooManyAttempts = errors.New("account: too many confirmation attempts")
 	// ErrCodeMismatch is returned when the submitted code does not match.
 	ErrCodeMismatch = errors.New("account: confirmation code does not match")
+	// ErrTooManyRequests is returned when confirm-code sends to an address are being
+	// requested too frequently (the resend cooldown or the rolling-hour cap).
+	ErrTooManyRequests = errors.New("account: too many code requests")
+	// ErrNoEmail is returned when an email-code step-up is requested for an account that
+	// holds no confirmed email (the caller must use the typed-phrase path instead).
+	ErrNoEmail = errors.New("account: no confirmed email")
 )
 
 // EmailService runs the email confirm-code flow: it issues a 6-digit code over a
@@ -57,12 +80,78 @@ var (
 type EmailService struct {
 	store   *Store
 	mailer  Mailer
+	baseURL string
+	limiter *SendLimiter
 	now     func() time.Time
 }
 
-// NewEmailService constructs an EmailService over store, sending via mailer.
+// NewEmailService constructs an EmailService over store, sending via mailer. baseURL
-func NewEmailService(store *Store, mailer Mailer) *EmailService {
+// is the canonical public origin (scheme + host) used to build the one-tap confirm
-	return &EmailService{store: store, mailer: mailer, now: func() time.Time { return time.Now().UTC() }}
+// deeplink and the email footer landing link; an empty baseURL omits the deeplink
+// (development / log mailer).
+func NewEmailService(store *Store, mailer Mailer, baseURL string) *EmailService {
+	return &EmailService{store: store, mailer: mailer, baseURL: baseURL, now: func() time.Time { return time.Now().UTC() }}
+}
+
+// SetSendLimiter installs a per-recipient send throttle. When unset (nil), sends are
+// not throttled — production wires a limiter; tests leave it off.
+func (s *EmailService) SetSendLimiter(l *SendLimiter) { s.limiter = l }
+
+// allowSend reports whether a confirm-code send to email is permitted now, recording
+// it when so. A nil limiter permits every send.
+func (s *EmailService) allowSend(email string) bool {
+	return s.limiter == nil || s.limiter.Allow(email)
+}
+
+// issueCode generates a fresh confirm-code and one-tap deeplink token for (accountID,
+// email), replaces any prior pending confirmation, and mails the branded code in
+// locale; purpose selects the email wording and what verifying does. Only the SHA-256
+// hashes of the code and token are stored.
+func (s *EmailService) issueCode(ctx context.Context, accountID uuid.UUID, email, purpose, locale string) error {
+	code, codeHash, err := generateCode()
+	if err != nil {
+		return err
+	}
+	token, tokenHash, err := generateLinkToken()
+	if err != nil {
+		return err
+	}
+	if err := s.store.replacePendingConfirmation(ctx, accountID, email, codeHash, tokenHash, purpose, s.now().Add(emailCodeTTL)); err != nil {
+		return err
+	}
+	// Account deletion is never a one-tap link (a prefetch or a stray click must not delete
+	// an account): the delete code is entered in the app only, so the email omits the
+	// deeplink and ConfirmByToken refuses a delete token.
+	deeplink := s.confirmURL(token, locale)
+	if purpose == purposeDelete {
+		deeplink = ""
+	}
+	msg, err := renderConfirmationEmail(purpose, code, deeplink, s.baseURL, locale)
+	if err != nil {
+		return err
+	}
+	msg.To = email
+	return s.mailer.Send(ctx, msg)
+}
+
+// confirmURL builds the absolute one-tap confirm deeplink for token in locale, or ""
+// when no public base URL is configured. The locale rides the fragment as ?lang so the
+// confirm screen (opened in a browser with no session) renders in the email's language.
+func (s *EmailService) confirmURL(token, locale string) string {
+	if s.baseURL == "" {
+		return ""
+	}
+	return strings.TrimRight(s.baseURL, "/") + emailConfirmPath + token + "?lang=" + normalizeLocale(locale)
+}
+
+// accountLocale returns the account's preferred UI language for localising email,
+// defaulting to "en" when the account cannot be loaded.
+func (s *EmailService) accountLocale(ctx context.Context, accountID uuid.UUID) string {
+	acc, err := s.store.GetByID(ctx, accountID)
+	if err != nil {
+		return "en"
+	}
+	return acc.PreferredLanguage
 }
 
 // RequestCode issues a fresh confirm-code for email to accountID and mails it,
@@ -73,6 +162,9 @@ func (s *EmailService) RequestCode(ctx context.Context, accountID uuid.UUID, ema
 	if err != nil {
 		return err
 	}
+	if !s.allowSend(addr) {
+		return ErrTooManyRequests
+	}
 	owner, ok, err := s.store.confirmedEmailAccount(ctx, addr)
 	if err != nil {
 		return err
@@ -83,16 +175,7 @@ func (s *EmailService) RequestCode(ctx context.Context, accountID uuid.UUID, ema
 		}
 		return ErrEmailTaken
 	}
-	code, hash, err := generateCode()
+	return s.issueCode(ctx, accountID, addr, purposeLink, s.accountLocale(ctx, accountID))
-	if err != nil {
-		return err
-	}
-	if err := s.store.replacePendingConfirmation(ctx, accountID, addr, hash, s.now().Add(emailCodeTTL)); err != nil {
-		return err
-	}
-	subject := "Your Scrabble confirmation code"
-	body := fmt.Sprintf("Your confirmation code is %s. It expires in %d minutes.", code, int(emailCodeTTL/time.Minute))
-	return s.mailer.Send(ctx, addr, subject, body)
 }
 
 // ConfirmCode verifies code for accountID and email. On success it attaches a
@@ -123,34 +206,35 @@ func (s *EmailService) ConfirmCode(ctx context.Context, accountID uuid.UUID, ema
 	if err := s.store.confirmEmailIdentity(ctx, conf.id, accountID, addr, s.now()); err != nil {
 		return Account{}, err
 	}
+	// Binding the first confirmed email promotes a guest to a durable account, matching the
+	// link and deeplink flows (defence-in-depth: no confirmed-email path leaves is_guest set).
+	if err := s.store.ClearGuest(ctx, accountID); err != nil {
+		return Account{}, err
+	}
 	return s.store.GetByID(ctx, accountID)
 }
 
 // RequestLoginCode issues a login confirm-code to the account that owns email,
-// provisioning a fresh (unconfirmed) durable account when the email is new. It is
+// provisioning a fresh (unconfirmed) guest account when the email is new — it becomes
-// the unauthenticated email-login entry point and, unlike RequestCode,
+// durable once the code is confirmed. It is the unauthenticated email-login entry
-// does not refuse an already-confirmed email — that is the ordinary returning-user
+// point and, unlike RequestCode, does not refuse an already-confirmed email — that is
-// login. The code is mailed to the address, so only its real owner can complete
+// the ordinary returning-user login. The code is mailed to the address, so only its
-// the login. It returns the target account id for the subsequent LoginWithCode.
+// real owner can complete the login. On first contact browserTZ (the client's
-func (s *EmailService) RequestLoginCode(ctx context.Context, email string) (uuid.UUID, error) {
+// detected "±HH:MM" UTC offset) seeds the new account's time zone and language its UI
+// language. It returns the target account id for the subsequent LoginWithCode.
+func (s *EmailService) RequestLoginCode(ctx context.Context, email, browserTZ, language string) (uuid.UUID, error) {
 	addr, err := normalizeEmail(email)
 	if err != nil {
 		return uuid.UUID{}, err
 	}
-	acc, err := s.store.ProvisionByIdentity(ctx, KindEmail, addr)
+	if !s.allowSend(addr) {
+		return uuid.UUID{}, ErrTooManyRequests
+	}
+	acc, err := s.store.ProvisionEmail(ctx, addr, browserTZ, language)
 	if err != nil {
 		return uuid.UUID{}, err
 	}
-	code, hash, err := generateCode()
+	if err := s.issueCode(ctx, acc.ID, addr, purposeLogin, language); err != nil {
-	if err != nil {
-		return uuid.UUID{}, err
-	}
-	if err := s.store.replacePendingConfirmation(ctx, acc.ID, addr, hash, s.now().Add(emailCodeTTL)); err != nil {
-		return uuid.UUID{}, err
-	}
-	subject := "Your Scrabble login code"
-	body := fmt.Sprintf("Your login code is %s. It expires in %d minutes.", code, int(emailCodeTTL/time.Minute))
-	if err := s.mailer.Send(ctx, addr, subject, body); err != nil {
 		return uuid.UUID{}, err
 	}
 	return acc.ID, nil
@@ -189,9 +273,104 @@ func (s *EmailService) LoginWithCode(ctx context.Context, email, code string) (A
 	if err := s.store.confirmEmailLogin(ctx, conf.id, acc.ID, addr, s.now()); err != nil {
 		return Account{}, err
 	}
+	if err := s.store.ClearGuest(ctx, acc.ID); err != nil {
+		return Account{}, err
+	}
 	return s.store.GetByID(ctx, acc.ID)
 }
 
+// LinkConfirmation is the outcome of confirming a one-tap deeplink token: what the
+// transport layer must finish. Purpose is the pending row's purpose. For a login,
+// Account is the account to sign in. For a link, Account is the account the email was
+// (or would be) attached to; NeedsMerge is set when another account (MergeOwner)
+// already owns the address, so the caller drives the interactive merge instead of a
+// plain link — the token is left unconsumed for that merge step.
+type LinkConfirmation struct {
+	Purpose    string
+	Account    uuid.UUID
+	NeedsMerge bool
+	MergeOwner uuid.UUID
+}
+
+// IsLogin reports whether the confirmation is a login (the caller mints a session)
+// rather than a link (attach the identity, or drive a merge).
+func (r LinkConfirmation) IsLogin() bool { return r.Purpose == purposeLogin }
+
+// ConfirmByToken verifies a one-tap deeplink token and performs its purpose. A login
+// confirms the email identity, clears the guest flag and returns the account to sign
+// in. A link attaches the confirmed email to the pending account when the address is
+// free, or reports NeedsMerge when another account already owns it (leaving the token
+// live so the caller's merge step can re-verify). It returns ErrNoPendingCode when the
+// token matches no live confirmation and ErrCodeExpired when it has lapsed. The token
+// is high-entropy, so there is no wrong-attempt counter.
+func (s *EmailService) ConfirmByToken(ctx context.Context, token string) (LinkConfirmation, error) {
+	pend, err := s.store.pendingByTokenHash(ctx, hashCode(token))
+	if err != nil {
+		return LinkConfirmation{}, err
+	}
+	if s.now().After(pend.expiresAt) {
+		return LinkConfirmation{}, ErrCodeExpired
+	}
+	switch pend.purpose {
+	case purposeLogin:
+		if err := s.store.confirmEmailLogin(ctx, pend.id, pend.accountID, pend.email, s.now()); err != nil {
+			return LinkConfirmation{}, err
+		}
+		if err := s.store.ClearGuest(ctx, pend.accountID); err != nil {
+			return LinkConfirmation{}, err
+		}
+		return LinkConfirmation{Purpose: purposeLogin, Account: pend.accountID}, nil
+	case purposeLink:
+		owner, ok, err := s.store.confirmedEmailAccount(ctx, pend.email)
+		if err != nil {
+			return LinkConfirmation{}, err
+		}
+		if ok {
+			if owner == pend.accountID {
+				if err := s.store.consumeConfirmation(ctx, pend.id, s.now()); err != nil {
+					return LinkConfirmation{}, err
+				}
+				return LinkConfirmation{Purpose: purposeLink, Account: pend.accountID}, nil
+			}
+			return LinkConfirmation{Purpose: purposeLink, Account: pend.accountID, NeedsMerge: true, MergeOwner: owner}, nil
+		}
+		if err := s.store.confirmEmailIdentity(ctx, pend.id, pend.accountID, pend.email, s.now()); err != nil {
+			return LinkConfirmation{}, err
+		}
+		// Binding the first email promotes a guest to a durable account, matching the
+		// code-based link flow (which clears the guest flag in the link service).
+		if err := s.store.ClearGuest(ctx, pend.accountID); err != nil {
+			return LinkConfirmation{}, err
+		}
+		return LinkConfirmation{Purpose: purposeLink, Account: pend.accountID}, nil
+	case purposeChange:
+		owner, ok, err := s.store.confirmedEmailAccount(ctx, pend.email)
+		if err != nil {
+			return LinkConfirmation{}, err
+		}
+		if ok && owner != pend.accountID {
+			// The new address is confirmed by a different account: refuse without
+			// disclosing it (anti-enumeration). Unlike a link, a change never merges.
+			return LinkConfirmation{}, ErrEmailTaken
+		}
+		if ok && owner == pend.accountID {
+			if err := s.store.consumeConfirmation(ctx, pend.id, s.now()); err != nil {
+				return LinkConfirmation{}, err
+			}
+			return LinkConfirmation{Purpose: purposeChange, Account: pend.accountID}, nil
+		}
+		if err := s.store.replaceEmailIdentity(ctx, pend.id, pend.accountID, pend.email, s.now()); err != nil {
+			return LinkConfirmation{}, err
+		}
+		return LinkConfirmation{Purpose: purposeChange, Account: pend.accountID}, nil
+	case purposeDelete:
+		// Deletion is confirmed in the app with the code, never via a one-tap link.
+		return LinkConfirmation{}, fmt.Errorf("account: deletion cannot be confirmed by link")
+	default:
+		return LinkConfirmation{}, fmt.Errorf("account: unsupported confirmation purpose %q", pend.purpose)
+	}
+}
+
 // emailConfirmation is a pending confirm-code row in domain form.
 type emailConfirmation struct {
 	id        uuid.UUID
@@ -220,9 +399,30 @@ func (s *Store) confirmedEmailAccount(ctx context.Context, email string) (uuid.U
 	return row.AccountID, true, nil
 }
 
+// confirmedEmailOf returns the account's confirmed email address and true, or ("", false)
+// when it holds none. It backs the deletion step-up, which mails a code to the account's
+// own address.
+func (s *Store) confirmedEmailOf(ctx context.Context, accountID uuid.UUID) (string, bool, error) {
+	stmt := postgres.SELECT(table.Identities.ExternalID).
+		FROM(table.Identities).
+		WHERE(
+			table.Identities.AccountID.EQ(postgres.UUID(accountID)).
+				AND(table.Identities.Kind.EQ(postgres.String(KindEmail))).
+				AND(table.Identities.Confirmed.EQ(postgres.Bool(true))),
+		).LIMIT(1)
+	var row model.Identities
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return "", false, nil
+		}
+		return "", false, fmt.Errorf("account: confirmed email of %s: %w", accountID, err)
+	}
+	return row.ExternalID, true, nil
+}
+
 // replacePendingConfirmation clears any pending code for (accountID, email) and
 // inserts a fresh one, inside one transaction.
-func (s *Store) replacePendingConfirmation(ctx context.Context, accountID uuid.UUID, email, codeHash string, expiresAt time.Time) error {
+func (s *Store) replacePendingConfirmation(ctx context.Context, accountID uuid.UUID, email, codeHash, linkTokenHash, purpose string, expiresAt time.Time) error {
 	id, err := uuid.NewV7()
 	if err != nil {
 		return fmt.Errorf("account: new confirmation id: %w", err)
@@ -239,7 +439,8 @@ func (s *Store) replacePendingConfirmation(ctx context.Context, accountID uuid.U
 		ins := table.EmailConfirmations.INSERT(
 			table.EmailConfirmations.ConfirmationID, table.EmailConfirmations.AccountID,
 			table.EmailConfirmations.Email, table.EmailConfirmations.CodeHash, table.EmailConfirmations.ExpiresAt,
-		).VALUES(id, accountID, email, codeHash, expiresAt)
+			table.EmailConfirmations.LinkTokenHash, table.EmailConfirmations.Purpose,
+		).VALUES(id, accountID, email, codeHash, expiresAt, linkTokenHash, purpose)
 		if _, err := ins.ExecContext(ctx, tx); err != nil {
 			return fmt.Errorf("insert confirmation: %w", err)
 		}
@@ -272,6 +473,54 @@ func (s *Store) latestPendingConfirmation(ctx context.Context, accountID uuid.UU
 	}, nil
 }
 
+// pendingConfirmation is a pending confirm-code row loaded by its deeplink token, in
+// domain form.
+type pendingConfirmation struct {
+	id        uuid.UUID
+	accountID uuid.UUID
+	email     string
+	purpose   string
+	expiresAt time.Time
+}
+
+// pendingByTokenHash loads the unconsumed confirmation whose deeplink token hashes to
+// tokenHash, or ErrNoPendingCode. The high-entropy token needs no attempt counter, so
+// a partial-unique index guarantees at most one match.
+func (s *Store) pendingByTokenHash(ctx context.Context, tokenHash string) (pendingConfirmation, error) {
+	stmt := postgres.SELECT(table.EmailConfirmations.AllColumns).
+		FROM(table.EmailConfirmations).
+		WHERE(
+			table.EmailConfirmations.LinkTokenHash.EQ(postgres.String(tokenHash)).
+				AND(table.EmailConfirmations.ConsumedAt.IS_NULL()),
+		).LIMIT(1)
+	var row model.EmailConfirmations
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return pendingConfirmation{}, ErrNoPendingCode
+		}
+		return pendingConfirmation{}, fmt.Errorf("account: load confirmation by token: %w", err)
+	}
+	return pendingConfirmation{
+		id:        row.ConfirmationID,
+		accountID: row.AccountID,
+		email:     row.Email,
+		purpose:   row.Purpose,
+		expiresAt: row.ExpiresAt,
+	}, nil
+}
+
+// consumeConfirmation marks a confirmation consumed without writing an identity, used
+// for the idempotent already-linked deeplink path.
+func (s *Store) consumeConfirmation(ctx context.Context, id uuid.UUID, now time.Time) error {
+	upd := table.EmailConfirmations.UPDATE(table.EmailConfirmations.ConsumedAt).
+		SET(postgres.TimestampzT(now)).
+		WHERE(table.EmailConfirmations.ConfirmationID.EQ(postgres.UUID(id)))
+	if _, err := upd.ExecContext(ctx, s.db); err != nil {
+		return fmt.Errorf("account: consume confirmation: %w", err)
+	}
+	return nil
+}
+
 // bumpConfirmationAttempts increments a code's wrong-attempt counter by one.
 func (s *Store) bumpConfirmationAttempts(ctx context.Context, id uuid.UUID) error {
 	stmt := table.EmailConfirmations.
@@ -318,6 +567,69 @@ func (s *Store) confirmEmailIdentity(ctx context.Context, confirmationID, accoun
 	return nil
 }
 
+// replaceEmailIdentity consumes the confirmation, deletes the account's existing email
+// identity (freeing the old address) and inserts newEmail as its confirmed email, inside
+// one transaction. It backs the change-email flow. A unique-constraint violation — the
+// new address was confirmed elsewhere in the meantime — surfaces as ErrEmailTaken. When
+// the account holds no email identity yet the delete is a no-op, so this doubles as an
+// attach.
+func (s *Store) replaceEmailIdentity(ctx context.Context, confirmationID, accountID uuid.UUID, newEmail string, now time.Time) error {
+	identityID, err := uuid.NewV7()
+	if err != nil {
+		return fmt.Errorf("account: new identity id: %w", err)
+	}
+	err = withTx(ctx, s.db, func(tx *sql.Tx) error {
+		upd := table.EmailConfirmations.
+			UPDATE(table.EmailConfirmations.ConsumedAt).
+			SET(postgres.TimestampzT(now)).
+			WHERE(table.EmailConfirmations.ConfirmationID.EQ(postgres.UUID(confirmationID)))
+		if _, err := upd.ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("consume confirmation: %w", err)
+		}
+		// Journal the outgoing email before replacing it, so the legal dossier keeps the
+		// address the account used to hold (see retention.go).
+		var old model.Identities
+		sel := postgres.SELECT(
+			table.Identities.ExternalID, table.Identities.Confirmed, table.Identities.CreatedAt,
+		).FROM(table.Identities).WHERE(
+			table.Identities.AccountID.EQ(postgres.UUID(accountID)).
+				AND(table.Identities.Kind.EQ(postgres.String(KindEmail))),
+		).LIMIT(1)
+		switch err := sel.QueryContext(ctx, tx, &old); {
+		case err == nil:
+			if err := retainIdentityTx(ctx, tx, accountID, KindEmail, old.ExternalID, old.Confirmed, old.CreatedAt, retainChange); err != nil {
+				return err
+			}
+		case errors.Is(err, qrm.ErrNoRows):
+			// No prior email (this doubles as an attach); nothing to retain.
+		default:
+			return fmt.Errorf("load outgoing email identity: %w", err)
+		}
+		del := table.Identities.DELETE().WHERE(
+			table.Identities.AccountID.EQ(postgres.UUID(accountID)).
+				AND(table.Identities.Kind.EQ(postgres.String(KindEmail))),
+		)
+		if _, err := del.ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("delete old email identity: %w", err)
+		}
+		ins := table.Identities.INSERT(
+			table.Identities.IdentityID, table.Identities.AccountID, table.Identities.Kind,
+			table.Identities.ExternalID, table.Identities.Confirmed,
+		).VALUES(identityID, accountID, KindEmail, newEmail, true)
+		if _, err := ins.ExecContext(ctx, tx); err != nil {
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		if isUniqueViolation(err) {
+			return ErrEmailTaken
+		}
+		return fmt.Errorf("account: replace email identity: %w", err)
+	}
+	return nil
+}
+
 // confirmEmailLogin consumes the login code and marks the existing email
 // identity confirmed, inside one transaction. The identity already exists (a
 // login provisioned it), so this updates rather than inserts and is idempotent
@@ -365,6 +677,18 @@ func generateCode() (code, hash string, err error) {
 	return code, hashCode(code), nil
 }
 
+// generateLinkToken returns a fresh opaque one-tap confirm deeplink token (URL-safe
+// base64, 256-bit) and its hex SHA-256 hash. Only the hash is stored; the token
+// travels only in the emailed link, mirroring the session-token model.
+func generateLinkToken() (token, hash string, err error) {
+	buf := make([]byte, linkTokenBytes)
+	if _, err := crand.Read(buf); err != nil {
+		return "", "", fmt.Errorf("account: generate link token: %w", err)
+	}
+	token = base64.RawURLEncoding.EncodeToString(buf)
+	return token, hashCode(token), nil
+}
+
 // hashCode returns the hex-encoded SHA-256 of a confirm-code.
 func hashCode(code string) string {
 	sum := sha256.Sum256([]byte(code))

backend/internal/account/emailtemplate.go

@@ -0,0 +1,239 @@
+package account
+
+import (
+	"fmt"
+	"html/template"
+	"strings"
+	tmpltext "text/template"
+	"time"
+)
+
+// emailBrandColor is the single accent used in the confirmation email — a calm
+// tile green, matching the "no riot of colours" brief.
+const emailBrandColor = "#2f7d4f"
+
+// confirmEmailView is the fully-localised data the confirmation email templates
+// render. Every string is resolved before rendering, so the templates carry no
+// localisation logic.
+type confirmEmailView struct {
+	Brand        string
+	Heading      string
+	Intro        string
+	Code         string
+	Expiry       string
+	CTALabel     string
+	DeeplinkURL  string
+	FooterIgnore string
+	LandingURL   string
+	LandingLabel string
+	Preheader    string
+	Locale       string
+	Accent       string
+}
+
+// emailCopy is the purpose- and locale-specific wording of a confirmation email.
+type emailCopy struct {
+	Subject      string
+	Preheader    string
+	Heading      string
+	Intro        string
+	CTALabel     string
+	FooterIgnore string
+}
+
+// confirmEmailCopy holds the wording per (purpose, locale). Unknown purposes fall
+// back to the neutral link wording and unknown locales fall back to English.
+var confirmEmailCopy = map[string]map[string]emailCopy{
+	purposeLogin: {
+		"en": {
+			Subject:      "Your Erudit sign-in code",
+			Preheader:    "Your sign-in code",
+			Heading:      "Sign in to Erudit",
+			Intro:        "Enter this code to sign in:",
+			CTALabel:     "Sign in with one tap",
+			FooterIgnore: "If you didn't request this email, you can safely ignore it.",
+		},
+		"ru": {
+			Subject:      "Код для входа в Эрудит",
+			Preheader:    "Ваш код для входа",
+			Heading:      "Вход в Эрудит",
+			Intro:        "Введите этот код, чтобы войти в игру:",
+			CTALabel:     "Войти одним нажатием",
+			FooterIgnore: "Если вы не запрашивали это письмо, просто проигнорируйте его.",
+		},
+	},
+	purposeLink: {
+		"en": {
+			Subject:      "Your Erudit confirmation code",
+			Preheader:    "Your confirmation code",
+			Heading:      "Confirm your e-mail",
+			Intro:        "Enter this code to confirm your address:",
+			CTALabel:     "Confirm with one tap",
+			FooterIgnore: "If you didn't request this email, you can safely ignore it.",
+		},
+		"ru": {
+			Subject:      "Код подтверждения Эрудит",
+			Preheader:    "Ваш код подтверждения",
+			Heading:      "Подтверждение e-mail",
+			Intro:        "Введите этот код, чтобы подтвердить адрес:",
+			CTALabel:     "Подтвердить одним нажатием",
+			FooterIgnore: "Если вы не запрашивали это письмо, просто проигнорируйте его.",
+		},
+	},
+	purposeChange: {
+		"en": {
+			Subject:      "Confirm your new Erudit e-mail",
+			Preheader:    "Confirm your new address",
+			Heading:      "Confirm your new e-mail",
+			Intro:        "Enter this code to switch your account to this address:",
+			CTALabel:     "Confirm with one tap",
+			FooterIgnore: "If you didn't request this change, you can safely ignore it — your address stays the same.",
+		},
+		"ru": {
+			Subject:      "Подтвердите новый e-mail в Эрудит",
+			Preheader:    "Подтвердите новый адрес",
+			Heading:      "Смена e-mail",
+			Intro:        "Введите этот код, чтобы привязать аккаунт к новому адресу:",
+			CTALabel:     "Подтвердить одним нажатием",
+			FooterIgnore: "Если вы не запрашивали смену, просто проигнорируйте письмо — адрес останется прежним.",
+		},
+	},
+	purposeDelete: {
+		"en": {
+			Subject:      "Confirm your Erudit account deletion",
+			Preheader:    "Confirm account deletion",
+			Heading:      "Delete your account",
+			Intro:        "Enter this code in the app to permanently delete your account:",
+			CTALabel:     "",
+			FooterIgnore: "If you didn't request this, ignore it — your account stays as it is.",
+		},
+		"ru": {
+			Subject:      "Подтвердите удаление аккаунта Эрудит",
+			Preheader:    "Подтверждение удаления аккаунта",
+			Heading:      "Удаление аккаунта",
+			Intro:        "Введите этот код в приложении, чтобы удалить аккаунт без восстановления:",
+			CTALabel:     "",
+			FooterIgnore: "Если вы не запрашивали удаление, проигнорируйте письмо — аккаунт останется.",
+		},
+	},
+}
+
+// emailBrand is the brand wordmark per locale.
+var emailBrand = map[string]string{"en": "Erudit", "ru": "Эрудит"}
+
+// emailExpiry formats the code-lifetime line per locale (abbreviated minutes to
+// avoid plural agreement).
+func emailExpiry(locale string, d time.Duration) string {
+	min := int(d / time.Minute)
+	if locale == "ru" {
+		return fmt.Sprintf("Код действует %d мин.", min)
+	}
+	return fmt.Sprintf("The code is valid for %d minutes.", min)
+}
+
+// normalizeLocale maps an account language to a supported email locale, defaulting
+// to English.
+func normalizeLocale(locale string) string {
+	if locale == "ru" {
+		return "ru"
+	}
+	return "en"
+}
+
+// renderConfirmationEmail builds the branded confirmation email for purpose in
+// locale: a large readable code plus a one-tap deeplink button, with an
+// ignore-notice footer and a landing link. Both a plain-text body and an HTML
+// alternative are produced. deeplinkURL is the absolute /confirm link and
+// landingURL the public landing origin.
+func renderConfirmationEmail(purpose, code, deeplinkURL, landingURL, locale string) (Message, error) {
+	loc := normalizeLocale(locale)
+	byLocale, ok := confirmEmailCopy[purpose]
+	if !ok {
+		byLocale = confirmEmailCopy[purposeLink]
+	}
+	cp := byLocale[loc]
+	view := confirmEmailView{
+		Brand:        emailBrand[loc],
+		Heading:      cp.Heading,
+		Intro:        cp.Intro,
+		Code:         code,
+		Expiry:       emailExpiry(loc, emailCodeTTL),
+		CTALabel:     cp.CTALabel,
+		DeeplinkURL:  deeplinkURL,
+		FooterIgnore: cp.FooterIgnore,
+		LandingURL:   landingURL,
+		LandingLabel: emailBrand[loc],
+		Preheader:    cp.Preheader,
+		Locale:       loc,
+		Accent:       emailBrandColor,
+	}
+	var html strings.Builder
+	if err := confirmEmailHTML.Execute(&html, view); err != nil {
+		return Message{}, fmt.Errorf("account: render confirmation email (html): %w", err)
+	}
+	var text strings.Builder
+	if err := confirmEmailText.Execute(&text, view); err != nil {
+		return Message{}, fmt.Errorf("account: render confirmation email (text): %w", err)
+	}
+	return Message{Subject: cp.Subject, Text: text.String(), HTML: html.String()}, nil
+}
+
+// confirmEmailHTML is a compact, image-free, mobile-friendly HTML email. Layout is
+// table-based for broad mail-client compatibility and all styling is inlined
+// because clients strip <style> blocks.
+var confirmEmailHTML = template.Must(template.New("confirmEmailHTML").Parse(`<!DOCTYPE html>
+<html lang="{{.Locale}}">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>{{.Brand}}</title>
+</head>
+<body style="margin:0;padding:0;background:#f4f5f7;">
+<span style="display:none;max-height:0;overflow:hidden;opacity:0;">{{.Preheader}}</span>
+<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="background:#f4f5f7;padding:24px 12px;">
+<tr><td align="center">
+<table role="presentation" width="100%" cellpadding="0" cellspacing="0" style="max-width:460px;background:#ffffff;border:1px solid #e5e7eb;border-radius:14px;overflow:hidden;font-family:-apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;">
+<tr><td style="padding:28px 32px 4px;">
+<div style="font-size:15px;font-weight:700;letter-spacing:.04em;color:{{.Accent}};">{{.Brand}}</div>
+</td></tr>
+<tr><td style="padding:8px 32px 0;">
+<h1 style="margin:0;font-size:20px;line-height:1.3;color:#111827;font-weight:600;">{{.Heading}}</h1>
+<p style="margin:12px 0 0;font-size:15px;line-height:1.5;color:#374151;">{{.Intro}}</p>
+</td></tr>
+<tr><td style="padding:18px 32px 0;">
+<div style="font-size:34px;font-weight:700;letter-spacing:8px;text-align:center;color:#111827;background:#f3f4f6;border-radius:10px;padding:18px 0;font-family:'SFMono-Regular',Consolas,Menlo,monospace;">{{.Code}}</div>
+<p style="margin:10px 0 0;font-size:13px;line-height:1.5;color:#6b7280;text-align:center;">{{.Expiry}}</p>
+</td></tr>
+{{if .DeeplinkURL}}<tr><td style="padding:22px 32px 0;" align="center">
+<a href="{{.DeeplinkURL}}" style="display:inline-block;background:{{.Accent}};color:#ffffff;text-decoration:none;font-size:15px;font-weight:600;padding:12px 26px;border-radius:9px;">{{.CTALabel}}</a>
+</td></tr>
+{{end}}<tr><td style="padding:26px 32px 28px;">
+<hr style="border:none;border-top:1px solid #eceef1;margin:0 0 16px;">
+<p style="margin:0;font-size:12px;line-height:1.6;color:#9ca3af;">{{.FooterIgnore}}</p>
+<p style="margin:10px 0 0;font-size:12px;color:#9ca3af;"><a href="{{.LandingURL}}" style="color:#6b7280;text-decoration:none;">{{.LandingLabel}}</a></p>
+</td></tr>
+</table>
+</td></tr>
+</table>
+</body>
+</html>
+`))
+
+// confirmEmailText is the plain-text alternative (and multipart fallback).
+var confirmEmailText = tmpltext.Must(tmpltext.New("confirmEmailText").Parse(`{{.Brand}}
+
+{{.Heading}}
+
+{{.Intro}}
+
+    {{.Code}}
+
+{{.Expiry}}
+
+{{if .DeeplinkURL}}{{.CTALabel}}:
+{{.DeeplinkURL}}
+
+{{end}}—
+{{.FooterIgnore}}
+{{.LandingLabel}} — {{.LandingURL}}
+`))

backend/internal/account/emailtemplate_test.go

@@ -0,0 +1,54 @@
+package account
+
+import (
+	"strings"
+	"testing"
+)
+
+// TestRenderConfirmationEmail checks that each (purpose, locale) renders a localised
+// subject, embeds the code and the one-tap deeplink in both bodies, and produces HTML.
+func TestRenderConfirmationEmail(t *testing.T) {
+	const deeplink = "https://erudit-game.ru/app/#/confirm/tok123"
+	cases := []struct {
+		name, purpose, locale, subjectSub string
+	}{
+		{"login ru", purposeLogin, "ru", "вход"},
+		{"login en", purposeLogin, "en", "sign-in"},
+		{"link ru", purposeLink, "ru", "подтвержд"},
+		{"link en", purposeLink, "en", "confirmation"},
+		{"change ru", purposeChange, "ru", "новый"},
+		{"change en", purposeChange, "en", "new"},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			msg, err := renderConfirmationEmail(c.purpose, "123456", deeplink, "https://erudit-game.ru", c.locale)
+			if err != nil {
+				t.Fatalf("render: %v", err)
+			}
+			if !strings.Contains(strings.ToLower(msg.Subject), c.subjectSub) {
+				t.Errorf("subject %q does not contain %q", msg.Subject, c.subjectSub)
+			}
+			if !strings.Contains(msg.Text, "123456") || !strings.Contains(msg.HTML, "123456") {
+				t.Error("code missing from a body")
+			}
+			if !strings.Contains(msg.Text, deeplink) || !strings.Contains(msg.HTML, "confirm/tok123") {
+				t.Error("deeplink missing from a body")
+			}
+			if !strings.Contains(msg.HTML, "<html") {
+				t.Error("HTML body is not HTML")
+			}
+		})
+	}
+}
+
+// TestRenderConfirmationEmailUnknownLocaleDefaultsEnglish falls back to English for an
+// unsupported locale rather than erroring or emitting an empty subject.
+func TestRenderConfirmationEmailUnknownLocaleDefaultsEnglish(t *testing.T) {
+	msg, err := renderConfirmationEmail(purposeLogin, "000000", "", "https://erudit-game.ru", "de")
+	if err != nil {
+		t.Fatalf("render: %v", err)
+	}
+	if !strings.Contains(strings.ToLower(msg.Subject), "sign-in") {
+		t.Errorf("unknown locale should default to English, got subject %q", msg.Subject)
+	}
+}

backend/internal/account/link.go

@@ -2,6 +2,7 @@ package account
 
 import (
 	"context"
+	"database/sql"
 	"errors"
 	"fmt"
 	"time"
@@ -16,6 +17,68 @@ import (
 // belongs to another account; the caller turns it into a merge.
 var ErrIdentityTaken = errors.New("account: identity already linked to another account")
 
+// ErrLastIdentity is returned when removing an identity would leave the account with
+// none, making it unreachable after logout. The admin email-erase refuses it.
+var ErrLastIdentity = errors.New("account: cannot remove the last identity")
+
+// RemoveIdentity deletes the account's identity of the given kind (and, for an email,
+// any pending confirmations for it), freeing it for reuse. It refuses when that is the
+// account's only identity (ErrLastIdentity) — which would leave the account
+// unreachable — and returns ErrNotFound when the account has no identity of that kind.
+// It backs the profile Unlink control and the admin "erase email" action.
+func (s *Store) RemoveIdentity(ctx context.Context, accountID uuid.UUID, kind string) error {
+	ids, err := s.Identities(ctx, accountID)
+	if err != nil {
+		return err
+	}
+	var toRetain []Identity
+	others := 0
+	for _, id := range ids {
+		if id.Kind == kind {
+			toRetain = append(toRetain, id)
+		} else {
+			others++
+		}
+	}
+	if len(toRetain) == 0 {
+		return ErrNotFound
+	}
+	if others == 0 {
+		return ErrLastIdentity
+	}
+	return withTx(ctx, s.db, func(tx *sql.Tx) error {
+		// Journal the detached credential before removing it, so the legal dossier
+		// survives while the identity frees for reuse (see retention.go).
+		for _, id := range toRetain {
+			if err := retainIdentityTx(ctx, tx, accountID, id.Kind, id.ExternalID, id.Confirmed, id.CreatedAt, retainUnlink); err != nil {
+				return err
+			}
+		}
+		delID := table.Identities.DELETE().WHERE(
+			table.Identities.AccountID.EQ(postgres.UUID(accountID)).
+				AND(table.Identities.Kind.EQ(postgres.String(kind))),
+		)
+		if _, err := delID.ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("account: delete %s identity %s: %w", kind, accountID, err)
+		}
+		if kind == KindEmail {
+			delConf := table.EmailConfirmations.DELETE().WHERE(
+				table.EmailConfirmations.AccountID.EQ(postgres.UUID(accountID)),
+			)
+			if _, err := delConf.ExecContext(ctx, tx); err != nil {
+				return fmt.Errorf("account: delete email confirmations %s: %w", accountID, err)
+			}
+		}
+		return nil
+	})
+}
+
+// RemoveEmailIdentity erases the account's email identity. It backs the admin console's
+// "erase email" action; the user-facing profile never unlinks email (it is changed).
+func (s *Store) RemoveEmailIdentity(ctx context.Context, accountID uuid.UUID) error {
+	return s.RemoveIdentity(ctx, accountID, KindEmail)
+}
+
 // RequestLinkCode issues and mails a confirm-code for email to accountID,
 // replacing any prior pending code. Unlike RequestCode it never refuses up front
 // (taken or already-confirmed): possession of the address is the authorization for
@@ -26,16 +89,10 @@ func (s *EmailService) RequestLinkCode(ctx context.Context, accountID uuid.UUID,
 	if err != nil {
 		return err
 	}
-	code, hash, err := generateCode()
+	if !s.allowSend(addr) {
-	if err != nil {
+		return ErrTooManyRequests
-		return err
 	}
-	if err := s.store.replacePendingConfirmation(ctx, accountID, addr, hash, s.now().Add(emailCodeTTL)); err != nil {
+	return s.issueCode(ctx, accountID, addr, purposeLink, s.accountLocale(ctx, accountID))
-		return err
-	}
-	subject := "Your Scrabble confirmation code"
-	body := fmt.Sprintf("Your confirmation code is %s. It expires in %d minutes.", code, int(emailCodeTTL/time.Minute))
-	return s.mailer.Send(ctx, addr, subject, body)
 }
 
 // ConfirmLink verifies code for (accountID, email) and reports the address's
@@ -70,6 +127,100 @@ func (s *EmailService) ConfirmLink(ctx context.Context, accountID uuid.UUID, ema
 	return accountID, true, nil
 }
 
+// RequestChangeCode issues and mails a confirm-code to newEmail for an authenticated
+// email change on accountID, replacing any prior pending code. Like RequestLinkCode it
+// never refuses up front on "taken" (anti-enumeration): possession of newEmail is the
+// authorization, and a conflict with another account is revealed only at confirm — as a
+// non-disclosing refusal, never a merge.
+func (s *EmailService) RequestChangeCode(ctx context.Context, accountID uuid.UUID, newEmail string) error {
+	addr, err := normalizeEmail(newEmail)
+	if err != nil {
+		return err
+	}
+	if !s.allowSend(addr) {
+		return ErrTooManyRequests
+	}
+	return s.issueCode(ctx, accountID, addr, purposeChange, s.accountLocale(ctx, accountID))
+}
+
+// ConfirmChange verifies code for (accountID, newEmail) and atomically replaces the
+// account's confirmed email with newEmail, freeing the old address. When newEmail is
+// already confirmed by another account it refuses with ErrEmailTaken (surfaced to the
+// user as a non-disclosing "check the address or contact support"), never merging; when
+// the account already owns newEmail it is an idempotent no-op. It returns the usual
+// confirm-code errors (ErrNoPendingCode, ErrCodeExpired, ErrTooManyAttempts,
+// ErrCodeMismatch) and the updated account on success.
+func (s *EmailService) ConfirmChange(ctx context.Context, accountID uuid.UUID, newEmail, code string) (Account, error) {
+	addr, err := normalizeEmail(newEmail)
+	if err != nil {
+		return Account{}, err
+	}
+	conf, err := s.verifyPendingCode(ctx, accountID, addr, code)
+	if err != nil {
+		return Account{}, err
+	}
+	owner, ok, err := s.store.confirmedEmailAccount(ctx, addr)
+	if err != nil {
+		return Account{}, err
+	}
+	if ok && owner != accountID {
+		return Account{}, ErrEmailTaken
+	}
+	if ok && owner == accountID {
+		if err := s.store.consumeConfirmation(ctx, conf.id, s.now()); err != nil {
+			return Account{}, err
+		}
+		return s.store.GetByID(ctx, accountID)
+	}
+	if err := s.store.replaceEmailIdentity(ctx, conf.id, accountID, addr, s.now()); err != nil {
+		return Account{}, err
+	}
+	return s.store.GetByID(ctx, accountID)
+}
+
+// HasEmail reports whether accountID owns a confirmed email. The account-deletion step-up
+// mails a confirm-code when it does, and falls back to a typed phrase otherwise.
+func (s *EmailService) HasEmail(ctx context.Context, accountID uuid.UUID) (bool, error) {
+	_, ok, err := s.store.confirmedEmailOf(ctx, accountID)
+	return ok, err
+}
+
+// RequestDeleteCode mails an account-deletion confirm-code to the account's own confirmed
+// email (no deeplink — deletion is confirmed in the app). It returns ErrNoEmail when the
+// account holds no email, ErrTooManyRequests when throttled.
+func (s *EmailService) RequestDeleteCode(ctx context.Context, accountID uuid.UUID) error {
+	addr, ok, err := s.store.confirmedEmailOf(ctx, accountID)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return ErrNoEmail
+	}
+	if !s.allowSend(addr) {
+		return ErrTooManyRequests
+	}
+	return s.issueCode(ctx, accountID, addr, purposeDelete, s.accountLocale(ctx, accountID))
+}
+
+// VerifyDeleteCode verifies the account-deletion code against the account's own email and
+// consumes it on success. It returns ErrNoEmail (no email), the usual confirm-code errors
+// (ErrNoPendingCode, ErrCodeExpired, ErrTooManyAttempts, ErrCodeMismatch), or nil when the
+// code is valid — the caller then performs the deletion.
+func (s *EmailService) VerifyDeleteCode(ctx context.Context, accountID uuid.UUID, code string) error {
+	addr, ok, err := s.store.confirmedEmailOf(ctx, accountID)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return ErrNoEmail
+	}
+	conf, err := s.verifyPendingCode(ctx, accountID, addr, code)
+	if err != nil {
+		return err
+	}
+	return s.store.consumeConfirmation(ctx, conf.id, s.now())
+}
+
 // verifyPendingCode loads and checks the pending confirm-code for (accountID,
 // addr), counting a wrong attempt. It returns the confirmation on success.
 func (s *EmailService) verifyPendingCode(ctx context.Context, accountID uuid.UUID, addr, code string) (emailConfirmation, error) {

backend/internal/account/mailer.go

@@ -3,33 +3,99 @@ package account
 import (
 	"context"
 	"fmt"
-	"net"
+	"strconv"
-	"net/smtp"
+	"strings"
+	"time"
 
+	"github.com/wneessen/go-mail"
 	"go.uber.org/zap"
 )
 
+// Message is a transactional email to send through a Mailer. Text is the
+// required plain-text body and doubles as the multipart/alternative fallback;
+// HTML, when non-empty, is the preferred body a capable client renders instead.
+type Message struct {
+	// To is the recipient address, or several comma-separated (all get the one message).
+	To string
+	// From, when non-empty, overrides the configured sender for this message — the admin
+	// alert path uses a distinct From from the user-facing confirm-code sender.
+	From    string
+	Subject string
+	Text    string
+	HTML    string
+}
+
 // Mailer delivers a transactional email. It is the seam behind which the email
 // confirm-code flow sends codes, so the relay is swappable and unit tests use a
-// fixture (see docs/TESTING.md: no real network in tests). The context is offered
+// fixture (see docs/TESTING.md: no real network in tests). The context bounds the
-// for cancellation; the standard-library SMTP implementation sends synchronously
+// delivery and is honoured by the SMTP implementation.
-// and ignores it.
 type Mailer interface {
-	Send(ctx context.Context, to, subject, body string) error
+	Send(ctx context.Context, msg Message) error
+}
+
+// splitAddrs splits a comma-separated recipient list into trimmed, non-empty addresses.
+func splitAddrs(list string) []string {
+	parts := strings.Split(list, ",")
+	out := make([]string, 0, len(parts))
+	for _, p := range parts {
+		if a := strings.TrimSpace(p); a != "" {
+			out = append(out, a)
+		}
+	}
+	return out
 }
 
 // SMTPConfig configures the SMTP relay. An empty Host selects the LogMailer
 // instead, so a deployment without a relay still runs (the code lands in the log).
+// TLS is always used and no client certificate is required — only the server
+// certificate is validated against the system roots.
 type SMTPConfig struct {
 	Host     string
 	Port     string
 	Username string
 	Password string
 	From     string
+	// TLS selects the transport security: "ssl" for implicit TLS from connect, or
+	// "starttls" to upgrade a plaintext connection. Empty derives the mode from the
+	// port (implicit TLS on 465, STARTTLS otherwise); set it explicitly for a relay on
+	// a non-standard port (e.g. Selectel's 1127 = SSL, 1126 = STARTTLS).
+	TLS string
+	// AdminFrom / AdminTo drive the operator alert emails (new feedback / word complaints),
+	// distinct from the user-facing confirm-code sender. AdminTo may be several
+	// comma-separated addresses. Both empty disables the alert worker.
+	AdminFrom string
+	AdminTo   string
 }
 
-// SMTPMailer sends mail through an SMTP relay using the standard library. When a
+const (
-// username is set it authenticates with PLAIN; otherwise it relays unauthenticated.
+	// SMTP transport-security modes for SMTPConfig.TLS.
+	smtpTLSImplicit = "ssl"
+	smtpTLSSTARTTLS = "starttls"
+	// smtpDialTimeout bounds a single relay connect-and-send. The confirm-code send
+	// is synchronous on the request path, so an unreachable relay must fail fast
+	// rather than hold the request open.
+	smtpDialTimeout = 15 * time.Second
+)
+
+// tlsMode resolves the transport-security mode for the relay: the explicitly
+// configured SMTPConfig.TLS, or — when unset — implicit TLS on the conventional SSL
+// port 465 and STARTTLS on any other port.
+func (cfg SMTPConfig) tlsMode(port int) string {
+	switch strings.ToLower(strings.TrimSpace(cfg.TLS)) {
+	case smtpTLSImplicit, "tls":
+		return smtpTLSImplicit
+	case smtpTLSSTARTTLS:
+		return smtpTLSSTARTTLS
+	}
+	if port == 465 {
+		return smtpTLSImplicit
+	}
+	return smtpTLSSTARTTLS
+}
+
+// SMTPMailer sends mail through an SMTP relay using go-mail. When a username is
+// set it authenticates, auto-discovering the strongest mechanism the relay
+// advertises; otherwise it relays unauthenticated.
 type SMTPMailer struct {
 	cfg SMTPConfig
 }
@@ -39,29 +105,55 @@ func NewSMTPMailer(cfg SMTPConfig) SMTPMailer {
 	return SMTPMailer{cfg: cfg}
 }
 
-// Send delivers a plain-text UTF-8 message to to via the configured relay.
+// Send delivers a UTF-8 message to msg.To via the configured relay. When msg.HTML
-func (m SMTPMailer) Send(_ context.Context, to, subject, body string) error {
+// is set the message is multipart/alternative (plain text plus HTML); otherwise
-	addr := net.JoinHostPort(m.cfg.Host, m.cfg.Port)
+// it is plain text only.
-	var auth smtp.Auth
+func (m SMTPMailer) Send(ctx context.Context, msg Message) error {
-	if m.cfg.Username != "" {
+	port, err := strconv.Atoi(m.cfg.Port)
-		auth = smtp.PlainAuth("", m.cfg.Username, m.cfg.Password, m.cfg.Host)
+	if err != nil {
+		return fmt.Errorf("account: invalid SMTP port %q: %w", m.cfg.Port, err)
 	}
-	if err := smtp.SendMail(addr, auth, m.cfg.From, []string{to}, message(m.cfg.From, to, subject, body)); err != nil {
+	opts := []mail.Option{mail.WithPort(port), mail.WithTimeout(smtpDialTimeout)}
-		return fmt.Errorf("account: send mail to %s: %w", to, err)
+	if m.cfg.tlsMode(port) == smtpTLSImplicit {
+		opts = append(opts, mail.WithSSL())
+	} else {
+		opts = append(opts, mail.WithTLSPortPolicy(mail.TLSMandatory))
+	}
+	if m.cfg.Username != "" {
+		opts = append(opts,
+			mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover),
+			mail.WithUsername(m.cfg.Username),
+			mail.WithPassword(m.cfg.Password),
+		)
+	}
+	client, err := mail.NewClient(m.cfg.Host, opts...)
+	if err != nil {
+		return fmt.Errorf("account: build mail client: %w", err)
+	}
+	out := mail.NewMsg()
+	from := m.cfg.From
+	if msg.From != "" {
+		from = msg.From
+	}
+	if err := out.From(from); err != nil {
+		return fmt.Errorf("account: set From %q: %w", from, err)
+	}
+	// To may carry several comma-separated recipients; go-mail wants them as separate
+	// arguments (a single joined string parses as one malformed address).
+	if err := out.To(splitAddrs(msg.To)...); err != nil {
+		return fmt.Errorf("account: set To %q: %w", msg.To, err)
+	}
+	out.Subject(msg.Subject)
+	out.SetBodyString(mail.TypeTextPlain, msg.Text)
+	if msg.HTML != "" {
+		out.AddAlternativeString(mail.TypeTextHTML, msg.HTML)
+	}
+	if err := client.DialAndSendWithContext(ctx, out); err != nil {
+		return fmt.Errorf("account: send mail to %s: %w", msg.To, err)
 	}
 	return nil
 }
 
-// message renders a minimal RFC 5322 plain-text email.
-func message(from, to, subject, body string) []byte {
-	return []byte("From: " + from + "\r\n" +
-		"To: " + to + "\r\n" +
-		"Subject: " + subject + "\r\n" +
-		"MIME-Version: 1.0\r\n" +
-		"Content-Type: text/plain; charset=UTF-8\r\n" +
-		"\r\n" + body + "\r\n")
-}
-
 // LogMailer logs the message instead of sending it. It is the default when no
 // SMTP relay is configured and is intended for development only: it logs the body,
 // which carries the confirm-code, so it must not be used in production.
@@ -74,11 +166,12 @@ func NewLogMailer(log *zap.Logger) LogMailer {
 	return LogMailer{log: log}
 }
 
-// Send logs the message at info level and reports success.
+// Send logs the message at info level and reports success. It logs the plain-text
-func (m LogMailer) Send(_ context.Context, to, subject, body string) error {
+// body only (which carries the confirm-code); the HTML alternative is omitted.
+func (m LogMailer) Send(_ context.Context, msg Message) error {
 	if m.log != nil {
 		m.log.Info("email not sent (log mailer)",
-			zap.String("to", to), zap.String("subject", subject), zap.String("body", body))
+			zap.String("to", msg.To), zap.String("subject", msg.Subject), zap.String("body", msg.Text))
 	}
 	return nil
 }

backend/internal/account/mailer_test.go

@@ -0,0 +1,51 @@
+package account
+
+import (
+	"slices"
+	"testing"
+)
+
+// TestSplitAddrs covers the comma-separated recipient parsing used for the admin alert
+// To (several operator mailboxes in one message), including trimming and empty entries.
+func TestSplitAddrs(t *testing.T) {
+	cases := []struct {
+		in   string
+		want []string
+	}{
+		{"a@x.ru", []string{"a@x.ru"}},
+		{"a@x.ru, b@y.ru", []string{"a@x.ru", "b@y.ru"}},
+		{" a@x.ru ,, b@y.ru ,", []string{"a@x.ru", "b@y.ru"}},
+		{"", nil},
+	}
+	for _, c := range cases {
+		if got := splitAddrs(c.in); !slices.Equal(got, c.want) {
+			t.Errorf("splitAddrs(%q) = %v, want %v", c.in, got, c.want)
+		}
+	}
+}
+
+// TestSMTPTLSMode covers the explicit TLS mode and the port-based fallback, including
+// the non-standard Selectel ports (1127 = SSL, 1126 = STARTTLS) that the 465 heuristic
+// alone cannot classify.
+func TestSMTPTLSMode(t *testing.T) {
+	cases := []struct {
+		name string
+		tls  string
+		port int
+		want string
+	}{
+		{"explicit ssl on a custom port (Selectel 1127)", "ssl", 1127, smtpTLSImplicit},
+		{"explicit starttls on a custom port (Selectel 1126)", "starttls", 1126, smtpTLSSTARTTLS},
+		{"tls is an alias for ssl", "TLS", 2525, smtpTLSImplicit},
+		{"empty derives implicit TLS on 465", "", 465, smtpTLSImplicit},
+		{"empty derives STARTTLS on 587", "", 587, smtpTLSSTARTTLS},
+		{"an unknown value falls back to the port heuristic", "bogus", 465, smtpTLSImplicit},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			if got := (SMTPConfig{TLS: c.tls}).tlsMode(c.port); got != c.want {
+				t.Errorf("tlsMode(TLS=%q, port=%d) = %q, want %q", c.tls, c.port, got, c.want)
+			}
+		})
+	}
+}

backend/internal/account/profile.go

@@ -101,6 +101,66 @@ func validateVariantPreferences(prefs []string) ([]string, error) {
 	return out, nil
 }
 
+// variantSeedPrefix marks a Telegram start-param payload that seeds a brand-new
+// account's variant preferences (e.g. "verudit_ru-scrabble_en"): the prefix, then the
+// canonical variant labels joined by "-". It is deliberately distinct from the routing
+// deep links (g/i/f; see platform/telegram .../deeplink) so the client's start-param
+// router falls through to the lobby for it.
+const variantSeedPrefix = "v"
+
+// SeedVariantsFromStartParam decodes a promo deep-link start-param into the variant
+// preference set to seed onto a brand-new account: the variantSeedPrefix followed by
+// the canonical variant labels joined by "-" (e.g. "verudit_ru-scrabble_en"). It
+// returns nil for any payload that is not a variant-seed link or that fails validation
+// against the known variants, so a malformed, empty or unrelated start-param simply
+// leaves the account on its default preferences rather than failing the login.
+func SeedVariantsFromStartParam(startParam string) []string {
+	if !strings.HasPrefix(startParam, variantSeedPrefix) {
+		return nil
+	}
+	body := strings.TrimPrefix(startParam, variantSeedPrefix)
+	if body == "" {
+		return nil
+	}
+	prefs, err := validateVariantPreferences(strings.Split(body, "-"))
+	if err != nil {
+		return nil
+	}
+	return prefs
+}
+
+// SetVariantPreferences overwrites only the variant-preference set of the account,
+// cleaning it to a deduplicated, canonically ordered subset of the known variants
+// (rejecting an empty or unknown set with ErrInvalidProfile) and bumping updated_at; it
+// reports ErrNotFound when no account matches id. It is the narrow counterpart to
+// UpdateProfile used to seed a promo-onboarded account's variants at first contact
+// without disturbing its other profile fields.
+func (s *Store) SetVariantPreferences(ctx context.Context, id uuid.UUID, prefs []string) (Account, error) {
+	clean, err := validateVariantPreferences(prefs)
+	if err != nil {
+		return Account{}, err
+	}
+	stmt := table.Accounts.UPDATE(
+		table.Accounts.VariantPreferences, table.Accounts.UpdatedAt,
+	).SET(
+		// clean is validated against the closed knownVariants set; bind as a text[]
+		// parameter (lib/pq encodes the array, the cast pins the column type), mirroring
+		// UpdateProfile.
+		postgres.Raw("#variant_prefs::text[]", map[string]interface{}{"#variant_prefs": pq.StringArray(clean)}),
+		postgres.TimestampzT(time.Now().UTC()),
+	).WHERE(table.Accounts.AccountID.EQ(postgres.UUID(id))).
+		RETURNING(table.Accounts.AllColumns)
+
+	var row model.Accounts
+	if err := stmt.QueryContext(ctx, s.db, &row); err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return Account{}, ErrNotFound
+		}
+		return Account{}, fmt.Errorf("account: set variant preferences %s: %w", id, err)
+	}
+	return modelToAccount(row), nil
+}
+
 // UpdateProfile validates and overwrites the editable fields of the account, then
 // returns the stored row. It reports ErrInvalidProfile for a bad language,
 // timezone or display name and ErrNotFound when no account matches id.

backend/internal/account/provision_test.go

@@ -75,3 +75,55 @@ func TestTelegramSeedTruncatesLongName(t *testing.T) {
 		t.Errorf("display name rune count = %d, want %d", n, maxDisplayName)
 	}
 }
+
+// TestVKSeed covers the pure mapping from VK launch fields to the create-time account
+// seed: supported-language detection from vk_language (bare and region-tagged) and the
+// display name sanitized from the client-supplied name. Unlike Telegram there is no
+// @username fallback — VK provides only the name.
+func TestVKSeed(t *testing.T) {
+	cases := map[string]struct {
+		languageCode, displayName string
+		wantLang, wantName        string
+	}{
+		"ru bare":          {"ru", "Иван", "ru", "Иван"},
+		"en region-tagged": {"en-US", "John", "en", "John"},
+		"full name kept":   {"ru", "Иван Петров", "ru", "Иван Петров"},
+		"unknown language": {"uk", "Тарас", "", "Тарас"},
+		"empty language":   {"", "Neo", "", "Neo"},
+		"trimmed":          {" RU ", "  Anna  ", "ru", "Anna"},
+		"emoji stripped":   {"en", "🎮Kaya🎮", "en", "Kaya"},
+	}
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			got := vkSeed(tc.languageCode, tc.displayName)
+			if got.preferredLanguage != tc.wantLang {
+				t.Errorf("preferredLanguage = %q, want %q", got.preferredLanguage, tc.wantLang)
+			}
+			if got.displayName != tc.wantName {
+				t.Errorf("displayName = %q, want %q", got.displayName, tc.wantName)
+			}
+		})
+	}
+}
+
+// TestVKSeedPlaceholder checks a VK name with no usable letters falls back to a
+// generated placeholder in the seeded language ("Player-NNNNN" / "Игрок-NNNNN").
+func TestVKSeedPlaceholder(t *testing.T) {
+	cases := map[string]struct {
+		languageCode, displayName string
+		wantRe                    string
+	}{
+		"en empty":     {"en", "", `^Player-\d{5}$`},
+		"ru empty":     {"ru", "", `^Игрок-\d{5}$`},
+		"default en":   {"uk", "", `^Player-\d{5}$`},
+		"name garbage": {"ru", "123!@#", `^Игрок-\d{5}$`},
+	}
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			got := vkSeed(tc.languageCode, tc.displayName).displayName
+			if !regexp.MustCompile(tc.wantRe).MatchString(got) {
+				t.Errorf("displayName = %q, want match %s", got, tc.wantRe)
+			}
+		})
+	}
+}

backend/internal/account/ratelimit.go

@@ -0,0 +1,66 @@
+package account
+
+import (
+	"sync"
+	"time"
+)
+
+// SendLimiter throttles confirm-code sends per recipient address: it enforces a
+// minimum cooldown between two sends and a cap over a rolling hour. It guards against
+// email bombing and protects the relay's own quota. State is in-memory (per process,
+// reset on restart) and keyed by the normalised recipient address, which is adequate
+// for the single-instance backend. Safe for concurrent use.
+type SendLimiter struct {
+	mu       sync.Mutex
+	cooldown time.Duration
+	perHour  int
+	now      func() time.Time
+	sends    map[string][]time.Time
+}
+
+// NewSendLimiter returns a SendLimiter allowing at most one send per cooldown and at
+// most perHour sends over any rolling hour, to the same recipient.
+func NewSendLimiter(cooldown time.Duration, perHour int) *SendLimiter {
+	return &SendLimiter{
+		cooldown: cooldown,
+		perHour:  perHour,
+		now:      func() time.Time { return time.Now() },
+		sends:    make(map[string][]time.Time),
+	}
+}
+
+// Allow reports whether a send to key is permitted now, recording the send when it is.
+// It is denied when the last send was within the cooldown or the rolling-hour cap is
+// already reached.
+func (l *SendLimiter) Allow(key string) bool {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	now := l.now()
+	cutoff := now.Add(-time.Hour)
+	kept := l.sends[key][:0]
+	for _, t := range l.sends[key] {
+		if t.After(cutoff) {
+			kept = append(kept, t)
+		}
+	}
+	if n := len(kept); n > 0 && now.Sub(kept[n-1]) < l.cooldown {
+		l.set(key, kept)
+		return false
+	}
+	if len(kept) >= l.perHour {
+		l.set(key, kept)
+		return false
+	}
+	l.set(key, append(kept, now))
+	return true
+}
+
+// set stores the retained send times for key, dropping the entry entirely once empty
+// so the map stays bounded to recipients active within the last hour.
+func (l *SendLimiter) set(key string, times []time.Time) {
+	if len(times) == 0 {
+		delete(l.sends, key)
+		return
+	}
+	l.sends[key] = times
+}

backend/internal/account/ratelimit_test.go

@@ -0,0 +1,43 @@
+package account
+
+import (
+	"testing"
+	"time"
+)
+
+// TestSendLimiter checks the per-recipient cooldown and the rolling-hour cap, and
+// that recipients are throttled independently.
+func TestSendLimiter(t *testing.T) {
+	base := time.Now()
+	now := base
+	l := NewSendLimiter(time.Minute, 3)
+	l.now = func() time.Time { return now }
+
+	if !l.Allow("a") {
+		t.Fatal("send 1 should be allowed")
+	}
+	if l.Allow("a") {
+		t.Fatal("immediate resend must be blocked by the cooldown")
+	}
+	if !l.Allow("b") {
+		t.Fatal("a different recipient is independent")
+	}
+
+	now = base.Add(time.Minute)
+	if !l.Allow("a") {
+		t.Fatal("send 2 after the cooldown should be allowed")
+	}
+	now = base.Add(2 * time.Minute)
+	if !l.Allow("a") {
+		t.Fatal("send 3 should be allowed")
+	}
+	now = base.Add(3 * time.Minute)
+	if l.Allow("a") {
+		t.Fatal("send 4 within the hour must be blocked by the cap")
+	}
+
+	now = base.Add(time.Hour + time.Minute)
+	if !l.Allow("a") {
+		t.Fatal("after the rolling hour the cap resets")
+	}
+}

backend/internal/account/retention.go

@@ -0,0 +1,224 @@
+package account
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/go-jet/jet/v2/postgres"
+	"github.com/go-jet/jet/v2/qrm"
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+
+	"scrabble/backend/internal/postgres/jet/backend/model"
+	"scrabble/backend/internal/postgres/jet/backend/table"
+)
+
+// RetentionTTL bounds how long the account-deletion legal dossier is kept before the
+// reaper purges it: two years from the detach/deletion event (owner policy, 2026-07-03).
+const RetentionTTL = 2 * 365 * 24 * time.Hour
+
+// Reasons recorded on a retained_identities row: what detached the credential from its
+// account (unlink / email change / account deletion here; an account merge that drops a
+// same-kind colliding identity writes reason "merge" from the accountmerge package). The
+// row is written just before the live identities row is removed, preserving the legal
+// dossier (which email/vk/tg was linked, and when) even as the identity frees for reuse.
+// See docs/ARCHITECTURE.md §9.1.
+const (
+	retainUnlink = "unlink"
+	retainChange = "change"
+	retainDelete = "delete"
+)
+
+// retainIdentityTx appends a retention-journal row for one identity being detached, inside
+// tx. linkedAt is the identity's original creation time; detached_at defaults to now(). It
+// must run in the same transaction as the identity removal, so the dossier and the live
+// state can never diverge.
+func retainIdentityTx(ctx context.Context, tx *sql.Tx, accountID uuid.UUID, kind, externalID string, confirmed bool, linkedAt time.Time, reason string) error {
+	id, err := uuid.NewV7()
+	if err != nil {
+		return fmt.Errorf("account: new retained id: %w", err)
+	}
+	ins := table.RetainedIdentities.INSERT(
+		table.RetainedIdentities.RetainedID, table.RetainedIdentities.AccountID,
+		table.RetainedIdentities.Kind, table.RetainedIdentities.ExternalID,
+		table.RetainedIdentities.Confirmed, table.RetainedIdentities.LinkedAt,
+		table.RetainedIdentities.Reason,
+	).VALUES(id, accountID, kind, externalID, confirmed, linkedAt, reason)
+	if _, err := ins.ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("account: retain identity (%s, %s): %w", kind, externalID, err)
+	}
+	return nil
+}
+
+// StampLastLogin records the account's last cold-load time and client IP, but only when
+// the stored value is missing or older than an hour — so it costs at most one write per
+// account per hour (its caller, the profile fetch, runs once per cold app-load). It is a
+// best-effort audit signal that feeds the account-deletion dossier.
+func (s *Store) StampLastLogin(ctx context.Context, accountID uuid.UUID, ip string) error {
+	now := time.Now().UTC()
+	upd := table.Accounts.UPDATE(table.Accounts.LastLoginAt, table.Accounts.LastLoginIP).
+		SET(postgres.TimestampzT(now), postgres.String(ip)).
+		WHERE(
+			table.Accounts.AccountID.EQ(postgres.UUID(accountID)).
+				AND(
+					table.Accounts.LastLoginAt.IS_NULL().
+						OR(table.Accounts.LastLoginAt.LT(postgres.TimestampzT(now.Add(-time.Hour)))),
+				),
+		)
+	if _, err := upd.ExecContext(ctx, s.db); err != nil {
+		return fmt.Errorf("account: stamp last login %s: %w", accountID, err)
+	}
+	return nil
+}
+
+// ReapExpiredRetention purges retention data whose event is older than cutoff: every
+// retained_identities row by its detached_at (covering unlink/change on live accounts as
+// well as deleted ones), plus — for accounts tombstoned before cutoff — the retained
+// feedback thread and the dossier PII (deleted_display_name, last_login_ip). Chat is kept
+// (a shared game artifact), and the tombstone account row itself stays (its no-cascade
+// foreign keys). It returns how many journal rows and feedback messages were removed.
+func (s *Store) ReapExpiredRetention(ctx context.Context, cutoff time.Time) (identities, feedback int64, err error) {
+	cut := postgres.TimestampzT(cutoff)
+	delJournal := table.RetainedIdentities.DELETE().
+		WHERE(table.RetainedIdentities.DetachedAt.LT(cut))
+	res, err := delJournal.ExecContext(ctx, s.db)
+	if err != nil {
+		return 0, 0, fmt.Errorf("account: reap retained identities: %w", err)
+	}
+	identities, _ = res.RowsAffected()
+
+	expired := postgres.SELECT(table.Accounts.AccountID).
+		FROM(table.Accounts).
+		WHERE(table.Accounts.DeletedAt.IS_NOT_NULL().AND(table.Accounts.DeletedAt.LT(cut)))
+	delFeedback := table.FeedbackMessages.DELETE().
+		WHERE(table.FeedbackMessages.AccountID.IN(expired))
+	fbRes, err := delFeedback.ExecContext(ctx, s.db)
+	if err != nil {
+		return identities, 0, fmt.Errorf("account: reap deleted feedback: %w", err)
+	}
+	feedback, _ = fbRes.RowsAffected()
+
+	clearPII := table.Accounts.UPDATE(table.Accounts.DeletedDisplayName, table.Accounts.LastLoginIP).
+		SET(postgres.NULL, postgres.NULL).
+		WHERE(
+			table.Accounts.DeletedAt.IS_NOT_NULL().
+				AND(table.Accounts.DeletedAt.LT(cut)).
+				AND(table.Accounts.DeletedDisplayName.IS_NOT_NULL().
+					OR(table.Accounts.LastLoginIP.IS_NOT_NULL())),
+		)
+	if _, err := clearPII.ExecContext(ctx, s.db); err != nil {
+		return identities, feedback, fmt.Errorf("account: clear expired dossier PII: %w", err)
+	}
+	return identities, feedback, nil
+}
+
+// RetainedIdentity is one row of the retention journal, for the admin dossier.
+type RetainedIdentity struct {
+	Kind       string
+	ExternalID string
+	Reason     string
+	Confirmed  bool
+	LinkedAt   time.Time
+	DetachedAt time.Time
+}
+
+// RetainedIdentities returns the account's retention-journal rows (the legal dossier of
+// detached credentials), newest detach first, for the admin console.
+func (s *Store) RetainedIdentities(ctx context.Context, accountID uuid.UUID) ([]RetainedIdentity, error) {
+	var rows []model.RetainedIdentities
+	err := postgres.SELECT(table.RetainedIdentities.AllColumns).
+		FROM(table.RetainedIdentities).
+		WHERE(table.RetainedIdentities.AccountID.EQ(postgres.UUID(accountID))).
+		ORDER_BY(table.RetainedIdentities.DetachedAt.DESC()).
+		QueryContext(ctx, s.db, &rows)
+	if err != nil && !errors.Is(err, qrm.ErrNoRows) {
+		return nil, fmt.Errorf("account: retained identities %s: %w", accountID, err)
+	}
+	out := make([]RetainedIdentity, 0, len(rows))
+	for _, r := range rows {
+		out = append(out, RetainedIdentity{
+			Kind: r.Kind, ExternalID: r.ExternalID, Reason: r.Reason,
+			Confirmed: r.Confirmed, LinkedAt: r.LinkedAt, DetachedAt: r.DetachedAt,
+		})
+	}
+	return out, nil
+}
+
+// DeletionInfo is a tombstoned account's dossier header, for the admin console.
+type DeletionInfo struct {
+	DeletedAt          *time.Time
+	DeletedDisplayName string
+	LastLoginAt        *time.Time
+	LastLoginIP        string
+}
+
+// DeletionInfo reads the account's deletion tombstone + last-login dossier fields.
+func (s *Store) DeletionInfo(ctx context.Context, accountID uuid.UUID) (DeletionInfo, error) {
+	var row model.Accounts
+	err := postgres.SELECT(
+		table.Accounts.DeletedAt, table.Accounts.DeletedDisplayName,
+		table.Accounts.LastLoginAt, table.Accounts.LastLoginIP,
+	).FROM(table.Accounts).
+		WHERE(table.Accounts.AccountID.EQ(postgres.UUID(accountID))).
+		QueryContext(ctx, s.db, &row)
+	if err != nil {
+		if errors.Is(err, qrm.ErrNoRows) {
+			return DeletionInfo{}, ErrNotFound
+		}
+		return DeletionInfo{}, fmt.Errorf("account: deletion info %s: %w", accountID, err)
+	}
+	info := DeletionInfo{DeletedAt: row.DeletedAt, LastLoginAt: row.LastLoginAt}
+	if row.DeletedDisplayName != nil {
+		info.DeletedDisplayName = *row.DeletedDisplayName
+	}
+	if row.LastLoginIP != nil {
+		info.LastLoginIP = *row.LastLoginIP
+	}
+	return info, nil
+}
+
+// RetentionReaper periodically purges expired account-deletion retention data via
+// Store.ReapExpiredRetention, mirroring GuestReaper: one background goroutine started once
+// from main.
+type RetentionReaper struct {
+	store *Store
+	ttl   time.Duration
+	clock func() time.Time
+	log   *zap.Logger
+}
+
+// NewRetentionReaper constructs a reaper purging retention data older than ttl. log may be
+// nil.
+func NewRetentionReaper(store *Store, ttl time.Duration, log *zap.Logger) *RetentionReaper {
+	if log == nil {
+		log = zap.NewNop()
+	}
+	return &RetentionReaper{
+		store: store,
+		ttl:   ttl,
+		clock: func() time.Time { return time.Now().UTC() },
+		log:   log,
+	}
+}
+
+// Run purges expired retention data on each tick until ctx is cancelled.
+func (r *RetentionReaper) Run(ctx context.Context, interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			idn, fb, err := r.store.ReapExpiredRetention(ctx, r.clock().Add(-r.ttl))
+			if err != nil {
+				r.log.Warn("retention reap failed", zap.Error(err))
+			} else if idn > 0 || fb > 0 {
+				r.log.Info("reaped expired retention", zap.Int64("identities", idn), zap.Int64("feedback", fb))
+			}
+		}
+	}
+}

backend/internal/account/userlist.go

@@ -19,6 +19,9 @@ type UserListItem struct {
 	PreferredLanguage string
 	IsGuest           bool
 	IsRobot           bool
+	// IsDeleted marks a tombstoned account (deleted_at set), shown as a badge — a search
+	// spans both lists, so a result can be either live or deleted.
+	IsDeleted bool
 	// FlaggedHighRateAt is the soft high-rate marker (zero when unflagged), shown
 	// as a badge in the console list.
 	FlaggedHighRateAt time.Time
@@ -26,13 +29,17 @@ type UserListItem struct {
 }
 
 // UserFilter narrows the admin user list: Robots selects robot accounts (otherwise the
-// non-robot "people"); NameMask and ExternalIDMask are glob masks ('*' = any run, '?' =
+// non-robot "people"); Deleted selects tombstoned accounts (every other scope hides them);
-// one char) matched case-insensitively against the display name / any identity's external
+// NameMask and ExternalIDMask are glob masks ('*' = any run, '?' = one char) matched
-// id. An empty mask means no filter on that field.
+// case-insensitively against the display name / any identity's external id; EmailExact is a
+// strict (exact) match against an account's email identity. An empty value means no filter
+// on that field.
 type UserFilter struct {
 	Robots         bool
+	Deleted        bool
 	NameMask       string
 	ExternalIDMask string
+	EmailExact     string
 }
 
 // robotExists is the correlated subquery testing whether account a is a robot.
@@ -51,17 +58,42 @@ func (s *Store) IsRobot(ctx context.Context, accountID uuid.UUID) (bool, error)
 	return ok, nil
 }
 
-// userListWhere builds the shared WHERE clause and its positional args (from $1).
+// userListWhere builds the shared WHERE clause and its positional args (from $1). On the
+// Robots tab it lists/searches robots only. Otherwise a search (any of the name /
+// external-id / email filters) spans live and deleted people alike — never robots — so the
+// operator finds a match from one query regardless of the People / Deleted tab; the search
+// also looks in the retention journal, so a deleted account is still found by the email /
+// external id it held (those rows moved from identities to retained_identities on deletion)
+// and by its retained real name. With no search, the People / Deleted tab scope applies.
 func userListWhere(f UserFilter) (string, []any) {
-	args := []any{f.Robots}
+	name := LikePattern(f.NameMask)
-	where := robotExists + ` = $1`
+	ext := LikePattern(f.ExternalIDMask)
-	if name := LikePattern(f.NameMask); name != "" {
+	email := strings.ToLower(strings.TrimSpace(f.EmailExact))
-		args = append(args, name)
+	searching := name != "" || ext != "" || email != ""
-		where += fmt.Sprintf(` AND a.display_name ILIKE $%d ESCAPE '\'`, len(args))
+
+	var args []any
+	var where string
+	switch {
+	case f.Robots:
+		where = robotExists + ` = true`
+	case searching:
+		where = robotExists + ` = false`
+	case f.Deleted:
+		where = robotExists + ` = false AND a.deleted_at IS NOT NULL`
+	default:
+		where = robotExists + ` = false AND a.deleted_at IS NULL`
 	}
-	if ext := LikePattern(f.ExternalIDMask); ext != "" {
+	if name != "" {
+		args = append(args, name)
+		where += fmt.Sprintf(` AND (a.display_name ILIKE $%d ESCAPE '\' OR a.deleted_display_name ILIKE $%d ESCAPE '\')`, len(args), len(args))
+	}
+	if ext != "" {
 		args = append(args, ext)
-		where += fmt.Sprintf(` AND EXISTS (SELECT 1 FROM backend.identities i WHERE i.account_id = a.account_id AND i.external_id ILIKE $%d ESCAPE '\')`, len(args))
+		where += fmt.Sprintf(` AND (EXISTS (SELECT 1 FROM backend.identities i WHERE i.account_id = a.account_id AND i.external_id ILIKE $%d ESCAPE '\') OR EXISTS (SELECT 1 FROM backend.retained_identities r WHERE r.account_id = a.account_id AND r.external_id ILIKE $%d ESCAPE '\'))`, len(args), len(args))
+	}
+	if email != "" {
+		args = append(args, email)
+		where += fmt.Sprintf(` AND (EXISTS (SELECT 1 FROM backend.identities i WHERE i.account_id = a.account_id AND i.kind = 'email' AND i.external_id = $%d) OR EXISTS (SELECT 1 FROM backend.retained_identities r WHERE r.account_id = a.account_id AND r.kind = 'email' AND r.external_id = $%d))`, len(args), len(args))
 	}
 	return where, args
 }
@@ -69,7 +101,7 @@ func userListWhere(f UserFilter) (string, []any) {
 // ListUsers returns the filtered admin user list, newest first, paginated.
 func (s *Store) ListUsers(ctx context.Context, f UserFilter, limit, offset int) ([]UserListItem, error) {
 	where, args := userListWhere(f)
-	q := `SELECT a.account_id, a.display_name, a.preferred_language, a.is_guest, a.flagged_high_rate_at, a.created_at, ` + robotExists + ` AS is_robot
+	q := `SELECT a.account_id, a.display_name, a.preferred_language, a.is_guest, a.flagged_high_rate_at, a.created_at, ` + robotExists + ` AS is_robot, (a.deleted_at IS NOT NULL) AS is_deleted
 FROM backend.accounts a WHERE ` + where +
 		fmt.Sprintf(` ORDER BY a.created_at DESC LIMIT $%d OFFSET $%d`, len(args)+1, len(args)+2)
 	args = append(args, limit, offset)
@@ -82,7 +114,7 @@ FROM backend.accounts a WHERE ` + where +
 	for rows.Next() {
 		var it UserListItem
 		var flagged sql.NullTime
-		if err := rows.Scan(&it.ID, &it.DisplayName, &it.PreferredLanguage, &it.IsGuest, &flagged, &it.CreatedAt, &it.IsRobot); err != nil {
+		if err := rows.Scan(&it.ID, &it.DisplayName, &it.PreferredLanguage, &it.IsGuest, &flagged, &it.CreatedAt, &it.IsRobot, &it.IsDeleted); err != nil {
 			return nil, fmt.Errorf("account: scan user: %w", err)
 		}
 		if flagged.Valid {

backend/internal/account/variant_seed_test.go

@@ -0,0 +1,37 @@
+package account
+
+import (
+	"slices"
+	"testing"
+)
+
+// TestSeedVariantsFromStartParam covers decoding a promo deep-link start-param into the
+// variant-preference set to seed: a valid "v"-prefixed, "-"-joined label list is cleaned
+// to the canonical order and deduplicated, while anything that is not a variant-seed link
+// or that names an unknown variant yields nil (leaving the account on its defaults).
+func TestSeedVariantsFromStartParam(t *testing.T) {
+	tests := []struct {
+		name  string
+		param string
+		want  []string
+	}{
+		{"english promo", "verudit_ru-scrabble_en", []string{"erudit_ru", "scrabble_en"}},
+		{"single variant", "vscrabble_en", []string{"scrabble_en"}},
+		{"canonical order regardless of payload order", "vscrabble_en-erudit_ru", []string{"erudit_ru", "scrabble_en"}},
+		{"deduplicated", "verudit_ru-erudit_ru", []string{"erudit_ru"}},
+		{"empty", "", nil},
+		{"prefix only", "v", nil},
+		{"routing game link is not a seed", "g0190abcd", nil},
+		{"friend code link is not a seed", "f123456", nil},
+		{"unknown variant rejected", "vscrabble_de", nil},
+		{"one unknown label rejects the whole set", "verudit_ru-scrabble_de", nil},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := SeedVariantsFromStartParam(tc.param)
+			if !slices.Equal(got, tc.want) {
+				t.Errorf("SeedVariantsFromStartParam(%q) = %v, want %v", tc.param, got, tc.want)
+			}
+		})
+	}
+}

backend/internal/accountdelete/delete.go

@@ -0,0 +1,223 @@
+// Package accountdelete deactivates an account as legal retention, not erasure: it keeps
+// the account row as a tombstone (its chat/complaint foreign keys have no cascade, so a
+// hard delete is impossible) while journalling and freeing the account's credentials,
+// anonymising the live surfaces, and dropping the account's own social/ephemeral rows.
+// The retained_identities journal plus the tombstone (deleted_at, deleted_display_name,
+// last_login_at/ip) form the admin/legal dossier; messages are deliberately kept. Session
+// revocation and active-game forfeit are orchestrated one layer up (they need the session
+// cache and the game service). See docs/ARCHITECTURE.md §9.1 and the retention TTL reaper.
+package accountdelete
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/go-jet/jet/v2/postgres"
+	"github.com/go-jet/jet/v2/qrm"
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/postgres/jet/backend/model"
+	"scrabble/backend/internal/postgres/jet/backend/table"
+)
+
+// AnonymizedName is the label a deleted account shows to opponents. Display names are
+// stored strings resolved identically for every viewer (no per-viewer localisation in this
+// codebase), so a single canonical label is used. The brackets are deliberate: the
+// editable-name rule (account.displayNameRe) forbids them, so a live player can never set a
+// name that impersonates a deleted account.
+const AnonymizedName = "[Deleted]"
+
+// retainDelete is the retained_identities reason written when a credential is journalled
+// because its account is being deleted.
+const retainDelete = "delete"
+
+// Deleter performs the SQL-atomic part of account deletion over a Postgres handle.
+type Deleter struct {
+	db  *sql.DB
+	now func() time.Time
+}
+
+// NewDeleter constructs a Deleter over db.
+func NewDeleter(db *sql.DB) *Deleter {
+	return &Deleter{db: db, now: func() time.Time { return time.Now().UTC() }}
+}
+
+// AnonymizeAndTombstone retires accountID atomically: it journals every live identity into
+// retained_identities (reason=delete) then removes them so the credentials free for reuse,
+// snapshots the real display name into deleted_display_name and scrubs the live one to
+// AnonymizedName, sets deleted_at, anonymises the account's game-seat snapshots, and drops
+// its friendships, blocks, invitations, friend codes, drafts and pending codes. Chat,
+// feedback and complaints are kept (the surviving tombstone keeps their no-cascade foreign
+// keys valid). It is idempotent-safe on an already-tombstoned account (re-journalling
+// nothing, since the identities are already gone).
+func (d *Deleter) AnonymizeAndTombstone(ctx context.Context, accountID uuid.UUID) error {
+	now := d.now()
+	return withTx(ctx, d.db, func(tx *sql.Tx) error {
+		if err := journalAndDropIdentities(ctx, tx, accountID, now); err != nil {
+			return err
+		}
+		if err := tombstone(ctx, tx, accountID, now); err != nil {
+			return err
+		}
+		if _, err := table.GamePlayers.UPDATE(table.GamePlayers.DisplayName).
+			SET(postgres.String(AnonymizedName)).
+			WHERE(table.GamePlayers.AccountID.EQ(postgres.UUID(accountID))).
+			ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("accountdelete: anonymise seats: %w", err)
+		}
+		return dropSocialAndEphemerals(ctx, tx, accountID)
+	})
+}
+
+// dropAllRobotGamesSQL deletes every game in which the account plays and no other seat is a
+// human — a robot seat is one whose account holds a 'robot' identity, so this covers both
+// honest vs-AI games and disguised auto-match substitutes. The game rows are deleted; their
+// moves/chat/players/complaints fall away through ON DELETE CASCADE.
+const dropAllRobotGamesSQL = `
+DELETE FROM games g
+WHERE EXISTS (
+    SELECT 1 FROM game_players p WHERE p.game_id = g.game_id AND p.account_id = $1
+) AND NOT EXISTS (
+    SELECT 1 FROM game_players o
+    WHERE o.game_id = g.game_id AND o.account_id <> $1
+      AND NOT EXISTS (
+          SELECT 1 FROM identities i WHERE i.account_id = o.account_id AND i.kind = 'robot'
+      )
+)`
+
+// DropAllRobotGames deletes the account's games that have no human opponent (solo vs-AI or
+// auto-match-robot games), returning how many were removed. Games with any human seat are
+// kept — their seat is anonymised by AnonymizeAndTombstone instead. Run it after the
+// account's active games are resigned, so no live game is removed under the robot driver.
+func (d *Deleter) DropAllRobotGames(ctx context.Context, accountID uuid.UUID) (int64, error) {
+	res, err := d.db.ExecContext(ctx, dropAllRobotGamesSQL, accountID)
+	if err != nil {
+		return 0, fmt.Errorf("accountdelete: drop all-robot games: %w", err)
+	}
+	n, err := res.RowsAffected()
+	if err != nil {
+		return 0, fmt.Errorf("accountdelete: dropped games count: %w", err)
+	}
+	return n, nil
+}
+
+// journalAndDropIdentities copies the account's live identities into the retention journal
+// (reason=delete) and then removes them, freeing each (kind, external_id) for reuse.
+func journalAndDropIdentities(ctx context.Context, tx *sql.Tx, accountID uuid.UUID, now time.Time) error {
+	var ids []model.Identities
+	err := postgres.SELECT(table.Identities.AllColumns).
+		FROM(table.Identities).
+		WHERE(table.Identities.AccountID.EQ(postgres.UUID(accountID))).
+		QueryContext(ctx, tx, &ids)
+	if err != nil && !errors.Is(err, qrm.ErrNoRows) {
+		return fmt.Errorf("accountdelete: load identities: %w", err)
+	}
+	for _, id := range ids {
+		rid, err := uuid.NewV7()
+		if err != nil {
+			return fmt.Errorf("accountdelete: new retained id: %w", err)
+		}
+		ins := table.RetainedIdentities.INSERT(
+			table.RetainedIdentities.RetainedID, table.RetainedIdentities.AccountID,
+			table.RetainedIdentities.Kind, table.RetainedIdentities.ExternalID,
+			table.RetainedIdentities.Confirmed, table.RetainedIdentities.LinkedAt,
+			table.RetainedIdentities.DetachedAt, table.RetainedIdentities.Reason,
+		).VALUES(rid, accountID, id.Kind, id.ExternalID, id.Confirmed, id.CreatedAt, now, retainDelete)
+		if _, err := ins.ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("accountdelete: retain identity %s: %w", id.Kind, err)
+		}
+	}
+	if _, err := table.Identities.DELETE().
+		WHERE(table.Identities.AccountID.EQ(postgres.UUID(accountID))).
+		ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete identities: %w", err)
+	}
+	return nil
+}
+
+// tombstone marks the account deleted, snapshotting the real display name into
+// deleted_display_name (evaluated from the old row) before scrubbing the live one.
+func tombstone(ctx context.Context, tx *sql.Tx, accountID uuid.UUID, now time.Time) error {
+	upd := table.Accounts.UPDATE(
+		table.Accounts.DeletedAt, table.Accounts.DeletedDisplayName,
+		table.Accounts.DisplayName, table.Accounts.UpdatedAt,
+	).SET(
+		postgres.TimestampzT(now), table.Accounts.DisplayName,
+		postgres.String(AnonymizedName), postgres.TimestampzT(now),
+	).WHERE(table.Accounts.AccountID.EQ(postgres.UUID(accountID)))
+	if _, err := upd.ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: tombstone account: %w", err)
+	}
+	return nil
+}
+
+// dropSocialAndEphemerals removes the account's own friendships, blocks, invitations
+// (as inviter and as invitee), friend codes, drafts and pending confirm-codes. These are
+// the deleting user's private data with no dossier value; chat and feedback are kept.
+func dropSocialAndEphemerals(ctx context.Context, tx *sql.Tx, accountID uuid.UUID) error {
+	id := postgres.UUID(accountID)
+	// Friendships and blocks are two-account edges keyed on either endpoint.
+	if _, err := table.Friendships.DELETE().
+		WHERE(table.Friendships.RequesterID.EQ(id).OR(table.Friendships.AddresseeID.EQ(id))).
+		ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete friendships: %w", err)
+	}
+	if _, err := table.Blocks.DELETE().
+		WHERE(table.Blocks.BlockerID.EQ(id).OR(table.Blocks.BlockedID.EQ(id))).
+		ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete blocks: %w", err)
+	}
+	// Invitations: drop the account's invitee rows, then its own invitations' invitees and
+	// the invitations themselves (children first, to respect the foreign key).
+	if _, err := table.GameInvitationInvitees.DELETE().
+		WHERE(table.GameInvitationInvitees.AccountID.EQ(id)).
+		ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete invitee rows: %w", err)
+	}
+	ownInvitations := postgres.SELECT(table.GameInvitations.InvitationID).
+		FROM(table.GameInvitations).
+		WHERE(table.GameInvitations.InviterID.EQ(id))
+	if _, err := table.GameInvitationInvitees.DELETE().
+		WHERE(table.GameInvitationInvitees.InvitationID.IN(ownInvitations)).
+		ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete own invitation invitees: %w", err)
+	}
+	if _, err := table.GameInvitations.DELETE().
+		WHERE(table.GameInvitations.InviterID.EQ(id)).
+		ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete invitations: %w", err)
+	}
+	// Ephemerals: friend codes, move drafts, pending confirm-codes.
+	if _, err := table.FriendCodes.DELETE().
+		WHERE(table.FriendCodes.AccountID.EQ(id)).ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete friend codes: %w", err)
+	}
+	if _, err := table.GameDrafts.DELETE().
+		WHERE(table.GameDrafts.AccountID.EQ(id)).ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete drafts: %w", err)
+	}
+	if _, err := table.EmailConfirmations.DELETE().
+		WHERE(table.EmailConfirmations.AccountID.EQ(id)).ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountdelete: delete confirmations: %w", err)
+	}
+	return nil
+}
+
+// withTx runs fn inside a transaction, committing on success and rolling back on error.
+func withTx(ctx context.Context, db *sql.DB, fn func(tx *sql.Tx) error) error {
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("accountdelete: begin tx: %w", err)
+	}
+	if err := fn(tx); err != nil {
+		_ = tx.Rollback()
+		return err
+	}
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("accountdelete: commit tx: %w", err)
+	}
+	return nil
+}

backend/internal/accountmerge/merge.go

@@ -27,6 +27,11 @@ import (
 // without taking a dependency on the game package.
 const statusActive = "active"
 
+// retainReasonMerge is the retained_identities.reason for a credential dropped by a merge
+// collision (both accounts held the same kind). It mirrors the account package's retain
+// reasons, kept local to avoid importing that package's unexported constants.
+const retainReasonMerge = "merge"
+
 // Friendship statuses, highest precedence first, mirroring internal/social.
 const (
 	friendAccepted = "accepted"
@@ -75,6 +80,9 @@ func (m *Merger) Merge(ctx context.Context, primary, secondary uuid.UUID) error
 		if err := mergeAccountFields(ctx, tx, primary, secondary, now); err != nil {
 			return err
 		}
+		if err := dedupeIdentities(ctx, tx, primary, secondary); err != nil {
+			return err
+		}
 		if err := reassignColumn(ctx, tx, table.Identities, table.Identities.AccountID, primary, secondary); err != nil {
 			return fmt.Errorf("accountmerge: identities: %w", err)
 		}
@@ -300,6 +308,77 @@ func reassignColumn(ctx context.Context, tx *sql.Tx, tbl postgres.Table, col pos
 	return err
 }
 
+// dedupeIdentities resolves a same-kind identity collision before the blanket identity
+// reassign: when both accounts already hold an identity of the same kind (e.g. each has a
+// confirmed email — reachable when two email-bearing accounts merge), the primary keeps
+// its own and the secondary's is journaled to retained_identities (reason=merge) and
+// removed. Without this the blanket reassign would leave the survivor with two identities
+// of one kind (there is no per-account-kind unique on identities), which the profile and
+// the retention dossier both treat as singular. Non-colliding identities are untouched and
+// move with the blanket reassign.
+func dedupeIdentities(ctx context.Context, tx *sql.Tx, primary, secondary uuid.UUID) error {
+	var prows []model.Identities
+	if err := postgres.SELECT(table.Identities.Kind).
+		FROM(table.Identities).
+		WHERE(table.Identities.AccountID.EQ(postgres.UUID(primary))).
+		QueryContext(ctx, tx, &prows); err != nil && !errors.Is(err, qrm.ErrNoRows) {
+		return fmt.Errorf("accountmerge: primary identity kinds: %w", err)
+	}
+	occupied := make(map[string]struct{}, len(prows))
+	for _, r := range prows {
+		occupied[r.Kind] = struct{}{}
+	}
+	if len(occupied) == 0 {
+		return nil
+	}
+	var srows []model.Identities
+	if err := postgres.SELECT(
+		table.Identities.Kind, table.Identities.ExternalID,
+		table.Identities.Confirmed, table.Identities.CreatedAt,
+	).FROM(table.Identities).
+		WHERE(table.Identities.AccountID.EQ(postgres.UUID(secondary))).
+		QueryContext(ctx, tx, &srows); err != nil && !errors.Is(err, qrm.ErrNoRows) {
+		return fmt.Errorf("accountmerge: secondary identities: %w", err)
+	}
+	for _, s := range srows {
+		if _, dup := occupied[s.Kind]; !dup {
+			continue
+		}
+		if err := retainMergedIdentity(ctx, tx, secondary, s); err != nil {
+			return err
+		}
+		del := table.Identities.DELETE().WHERE(
+			table.Identities.AccountID.EQ(postgres.UUID(secondary)).
+				AND(table.Identities.Kind.EQ(postgres.String(s.Kind))).
+				AND(table.Identities.ExternalID.EQ(postgres.String(s.ExternalID))),
+		)
+		if _, err := del.ExecContext(ctx, tx); err != nil {
+			return fmt.Errorf("accountmerge: drop colliding %s identity: %w", s.Kind, err)
+		}
+	}
+	return nil
+}
+
+// retainMergedIdentity appends a retained_identities row for a secondary identity dropped
+// by a merge collision (reason=merge), preserving it in the legal dossier. It mirrors
+// account.retainIdentityTx, which is unexported; detached_at falls to the column default.
+func retainMergedIdentity(ctx context.Context, tx *sql.Tx, accountID uuid.UUID, id model.Identities) error {
+	rid, err := uuid.NewV7()
+	if err != nil {
+		return fmt.Errorf("accountmerge: new retained id: %w", err)
+	}
+	ins := table.RetainedIdentities.INSERT(
+		table.RetainedIdentities.RetainedID, table.RetainedIdentities.AccountID,
+		table.RetainedIdentities.Kind, table.RetainedIdentities.ExternalID,
+		table.RetainedIdentities.Confirmed, table.RetainedIdentities.LinkedAt,
+		table.RetainedIdentities.Reason,
+	).VALUES(rid, accountID, id.Kind, id.ExternalID, id.Confirmed, id.CreatedAt, retainReasonMerge)
+	if _, err := ins.ExecContext(ctx, tx); err != nil {
+		return fmt.Errorf("accountmerge: retain merged %s identity: %w", id.Kind, err)
+	}
+	return nil
+}
+
 // friendRank ranks a friendship status for dedupe precedence (higher wins).
 func friendRank(status string) int {
 	switch status {

backend/internal/adminalert/notify.go

@@ -0,0 +1,116 @@
+// Package adminalert emails the operator when new player feedback or word complaints
+// arrive, coalescing a burst into a single digest per interval so a flood is one email,
+// not N. It is inert unless an admin sender and recipient are configured. The sender is
+// distinct from the user-facing confirm-code From, and the recipient may be several
+// comma-separated addresses (the mailer splits them).
+package adminalert
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"go.uber.org/zap"
+
+	"scrabble/backend/internal/account"
+)
+
+// FeedbackCounter counts feedback created since a time (satisfied by feedback.Service).
+type FeedbackCounter interface {
+	CountSince(ctx context.Context, since time.Time) (int, error)
+}
+
+// ComplaintCounter counts word complaints filed since a time (satisfied by game.Service).
+type ComplaintCounter interface {
+	CountComplaintsSince(ctx context.Context, since time.Time) (int, error)
+}
+
+// Notifier polls for new feedback and complaints and emails the operator a digest.
+type Notifier struct {
+	mailer     account.Mailer
+	feedback   FeedbackCounter
+	complaints ComplaintCounter
+	from       string
+	to         string
+	consoleURL string
+	clock      func() time.Time
+	log        *zap.Logger
+	last       time.Time
+}
+
+// New constructs a Notifier. from and to are the alert sender and recipient(s); consoleURL,
+// when non-empty, is the admin-console link included in the email. log may be nil. The
+// watermark starts at "now", so only items arriving after start-up are reported.
+func New(mailer account.Mailer, fb FeedbackCounter, cp ComplaintCounter, from, to, consoleURL string, log *zap.Logger) *Notifier {
+	if log == nil {
+		log = zap.NewNop()
+	}
+	return &Notifier{
+		mailer: mailer, feedback: fb, complaints: cp, from: from, to: to, consoleURL: consoleURL,
+		clock: func() time.Time { return time.Now().UTC() }, log: log, last: time.Now().UTC(),
+	}
+}
+
+// Run polls on each tick until ctx is cancelled.
+func (n *Notifier) Run(ctx context.Context, interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			n.tick(ctx)
+		}
+	}
+}
+
+// tick counts what arrived since the last watermark and, if anything did, emails one
+// digest. The watermark only advances after a successful send (or a quiet tick), so a
+// transient send failure is retried on the next tick — the counts simply grow.
+func (n *Notifier) tick(ctx context.Context) {
+	now := n.clock()
+	fb, err := n.feedback.CountSince(ctx, n.last)
+	if err != nil {
+		n.log.Warn("admin alert: count feedback failed", zap.Error(err))
+		return
+	}
+	cp, err := n.complaints.CountComplaintsSince(ctx, n.last)
+	if err != nil {
+		n.log.Warn("admin alert: count complaints failed", zap.Error(err))
+		return
+	}
+	if fb == 0 && cp == 0 {
+		n.last = now
+		return
+	}
+	if err := n.mailer.Send(ctx, n.digest(fb, cp)); err != nil {
+		n.log.Warn("admin alert: send failed", zap.Error(err))
+		return
+	}
+	n.log.Info("admin alert sent", zap.Int("feedback", fb), zap.Int("complaints", cp))
+	n.last = now
+}
+
+// digest builds the operator alert email for fb new feedback and cp new complaints.
+func (n *Notifier) digest(fb, cp int) account.Message {
+	var parts []string
+	if fb > 0 {
+		parts = append(parts, fmt.Sprintf("%d new feedback message(s)", fb))
+	}
+	if cp > 0 {
+		parts = append(parts, fmt.Sprintf("%d new word complaint(s)", cp))
+	}
+	summary := strings.Join(parts, ", ")
+	text := summary + "."
+	if n.consoleURL != "" {
+		text += "\n\nOpen the admin console: " + n.consoleURL
+	}
+	return account.Message{
+		From:    n.from,
+		To:      n.to,
+		Subject: "Erudit — " + summary,
+		Text:    text,
+	}
+}

backend/internal/adminalert/notify_test.go

@@ -0,0 +1,55 @@
+package adminalert
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"scrabble/backend/internal/account"
+)
+
+// The fakes ignore the watermark and return a fixed count, which is all the digest logic
+// needs.
+type fbCounter struct{ n int }
+
+func (f fbCounter) CountSince(context.Context, time.Time) (int, error) { return f.n, nil }
+
+type cpCounter struct{ n int }
+
+func (c cpCounter) CountComplaintsSince(context.Context, time.Time) (int, error) { return c.n, nil }
+
+type recordingMailer struct{ sent []account.Message }
+
+func (m *recordingMailer) Send(_ context.Context, msg account.Message) error {
+	m.sent = append(m.sent, msg)
+	return nil
+}
+
+func TestNotifierSkipsWhenNothingNew(t *testing.T) {
+	mailer := &recordingMailer{}
+	n := New(mailer, fbCounter{0}, cpCounter{0}, "alerts@erudit-game.ru", "op@x.ru", "", nil)
+	n.tick(context.Background())
+	if len(mailer.sent) != 0 {
+		t.Fatalf("sent %d emails, want 0 when nothing is new", len(mailer.sent))
+	}
+}
+
+func TestNotifierDigestsNewItems(t *testing.T) {
+	mailer := &recordingMailer{}
+	n := New(mailer, fbCounter{2}, cpCounter{1}, "alerts@erudit-game.ru", "op@x.ru, two@x.ru", "https://erudit-game.ru/_gm", nil)
+	n.tick(context.Background())
+	if len(mailer.sent) != 1 {
+		t.Fatalf("sent %d emails, want 1 digest", len(mailer.sent))
+	}
+	msg := mailer.sent[0]
+	if msg.From != "alerts@erudit-game.ru" || msg.To != "op@x.ru, two@x.ru" {
+		t.Errorf("digest addressing = From %q To %q", msg.From, msg.To)
+	}
+	if !strings.Contains(msg.Subject, "2 new feedback") || !strings.Contains(msg.Subject, "1 new word complaint") {
+		t.Errorf("digest subject = %q, want the feedback + complaint counts", msg.Subject)
+	}
+	if !strings.Contains(msg.Text, "/_gm") {
+		t.Errorf("digest body = %q, want the console link", msg.Text)
+	}
+}

backend/internal/adminconsole/render_test.go

@@ -24,6 +24,7 @@ func TestRendererRendersEveryPage(t *testing.T) {
 		{"dashboard", DashboardView{Accounts: 3, Variants: []VariantVersions{{Variant: "scrabble_en", Latest: "v1", Versions: []string{"v1"}}}}, "Dashboard"},
 		{"users", UsersView{Items: []UserRow{{ID: "a1", DisplayName: "Kaya", FlaggedHighRate: true}}, Pager: NewPager(1, 50, 1)}, "high-rate"},
 		{"user_detail", UserDetailView{ID: "a1", DisplayName: "Kaya", HasStats: true, Stats: StatsRow{Wins: 2}, TelegramID: "123", ConnectorEnabled: true}, "Send Telegram message"},
+		{"user_detail", UserDetailView{ID: "a1", DisplayName: "Kaya", VKID: "494075"}, "vk.com/id494075"},
 		{"user_detail", UserDetailView{ID: "a1", DisplayName: "Kaya", FlaggedHighRateAt: "2026-06-10 12:00"}, "Clear high-rate flag"},
 		{"user_detail", UserDetailView{ID: "a1", DisplayName: "Kaya", Roles: []string{"feedback_banned"}, KnownRoles: []string{"feedback_banned"}}, "feedback_banned"},
 		{"user_detail", UserDetailView{ID: "a1", DisplayName: "Kaya",

backend/internal/adminconsole/templates/pages/feedback_detail.gohtml

@@ -7,8 +7,9 @@
 <li><b>From</b> <a href="/_gm/users/{{.AccountID}}">{{.SenderName}}</a> ({{.Source}})</li>
 <li><b>Channel</b> {{.Channel}}</li>
 <li><b>Interface language</b> {{.InterfaceLanguage}}</li>
+<li><b>App version</b> {{if .Version}}<code>{{.Version}}</code>{{else}}<span class="note">unknown</span>{{end}}</li>
 <li><b>IP</b> {{if .IP}}<code>{{.IP}}</code>{{else}}<span class="note">none</span>{{end}}</li>
-<li><b>Filed</b> {{.CreatedAt}}</li>
+<li><b>Filed</b> {{.CreatedAt}} UTC &middot; browser {{if .CreatedAtBrowser}}{{.CreatedAtBrowser}} ({{.BrowserTZ}}){{else}}<span class="note">N/A</span>{{end}} &middot; user {{if .CreatedAtUser}}{{.CreatedAtUser}} ({{.UserTZ}}){{else}}<span class="note">N/A</span>{{end}}</li>
 <li><b>State</b> {{if .Archived}}archived{{else if .Read}}read{{else}}<span class="warn">unread</span>{{end}}</li>
 {{if .Banned}}<li><b>Feedback</b> <span class="warn">sender is banned from feedback</span></li>{{end}}
 </ul>

backend/internal/adminconsole/templates/pages/user_detail.gohtml

@@ -101,6 +101,29 @@
 {{else}}<tr><td colspan="4"><span class="note">no identities (guest)</span></td></tr>{{end}}
 </tbody>
 </table>
+{{if .HasEmail}}
+<form class="form" method="post" action="/_gm/users/{{.ID}}/remove-email" onsubmit="return confirm('Erase the email identity from this account? The address will be freed.')">
+<button type="submit">Erase email</button>
+</form>
+{{end}}
+</section>
+<section class="panel"><h2>Deletion &amp; retention</h2>
+{{if .LastLoginAt}}<p class="note">Last login: {{.LastLoginAt}}{{if .LastLoginIP}} — <code>{{.LastLoginIP}}</code>{{end}}</p>{{end}}
+{{if .Deleted}}<p><span class="warn">Deleted</span> at {{.DeletedAt}}{{if .DeletedName}} — was <code>{{.DeletedName}}</code>{{end}}</p>{{end}}
+{{if .Retained}}
+<h3>Retention journal (legal dossier of detached credentials)</h3>
+<table class="list">
+<thead><tr><th>Kind</th><th>Credential</th><th>Reason</th><th>Detached</th></tr></thead>
+<tbody>
+{{range .Retained}}<tr><td>{{.Kind}}</td><td><code>{{.ExternalID}}</code></td><td>{{.Reason}}</td><td>{{.DetachedAt}}</td></tr>{{end}}
+</tbody>
+</table>
+{{end}}
+{{if not .Deleted}}
+<form class="form" method="post" action="/_gm/users/{{.ID}}/delete" onsubmit="return confirm('Delete this account? Its credentials are journalled and freed, its data anonymised, and its sessions revoked. This cannot be undone.')">
+<button type="submit">Delete user</button>
+</form>
+{{end}}
 </section>
 <section class="panel"><h2>Friends</h2>
 <table class="list">
@@ -142,6 +165,11 @@
 {{else}}<p class="note">connector not configured (set BACKEND_CONNECTOR_ADDR)</p>{{end}}
 </section>
 {{end}}
+{{if .VKID}}
+<section class="panel"><h2>VK</h2>
+<p>VK ID: <code>{{.VKID}}</code> · <a href="https://vk.com/id{{.VKID}}" target="_blank" rel="noopener">open profile</a></p>
+</section>
+{{end}}
 <section class="panel"><h2>Games</h2>
 <table class="list">
 <thead><tr><th>Game</th><th>Variant</th><th>Status</th><th class="num">Players</th><th>Updated</th></tr></thead>

backend/internal/adminconsole/templates/pages/users.gohtml

@@ -2,13 +2,15 @@
 <h1>Users</h1>
 {{with .Data}}
 <nav class="subnav">
-<a href="/_gm/users"{{if not .Robots}} class="active"{{end}}>People</a> ·
+<a href="/_gm/users"{{if and (not .Robots) (not .Deleted)}} class="active"{{end}}>People</a> ·
+<a href="/_gm/users?kind=deleted"{{if .Deleted}} class="active"{{end}}>Deleted</a> ·
 <a href="/_gm/users?kind=robots"{{if .Robots}} class="active"{{end}}>Robots</a>
 </nav>
 <form class="form" method="get" action="/_gm/users">
-{{if .Robots}}<input type="hidden" name="kind" value="robots">{{end}}
+{{if .Robots}}<input type="hidden" name="kind" value="robots">{{end}}{{if .Deleted}}<input type="hidden" name="kind" value="deleted">{{end}}
 <input name="name" value="{{.NameMask}}" placeholder="display name mask (* ?)">
 <input name="ext" value="{{.ExternalIDMask}}" placeholder="external id mask (* ?)">
+<input name="email" value="{{.EmailExact}}" placeholder="email (exact)" type="search">
 <button type="submit">Filter</button>
 </form>
 <table class="list">
@@ -17,7 +19,7 @@
 {{range .Items}}
 <tr>
 <td><a href="/_gm/users/{{.ID}}">{{.ID}}</a></td>
-<td>{{.DisplayName}}{{if .Guest}} <span class="pill">guest</span>{{end}}{{if .FlaggedHighRate}} <span class="pill">high-rate</span>{{end}}</td>
+<td>{{.DisplayName}}{{if .Deleted}} <span class="pill">deleted</span>{{end}}{{if .Guest}} <span class="pill">guest</span>{{end}}{{if .FlaggedHighRate}} <span class="pill">high-rate</span>{{end}}</td>
 <td>{{.Kind}}</td>
 <td>{{.Language}}</td>
 <td>{{.CreatedAt}}</td>

backend/internal/adminconsole/views.go

@@ -60,8 +60,10 @@ type UsersView struct {
 	// be emitted verbatim — interpolated as a plain string it would have its "=" and "&"
 	// percent-encoded again by the contextual escaper.
 	Robots         bool
+	Deleted        bool
 	NameMask       string
 	ExternalIDMask string
+	EmailExact     string
 	FilterQuery    template.URL
 }
 
@@ -74,6 +76,7 @@ type UserRow struct {
 	Kind            string
 	Language        string
 	Guest           bool
+	Deleted         bool
 	FlaggedHighRate bool
 	CreatedAt       string
 	HasMoveStats    bool
@@ -150,6 +153,15 @@ type UserDetailView struct {
 	// MergedInto is the primary account id when this account has been retired by a
 	// merge, or empty for a live account.
 	MergedInto string
+	// The account-deletion dossier. Deleted marks a tombstoned account; DeletedAt and
+	// DeletedName are its deletion time and retained real name; LastLoginAt/IP are the
+	// last cold-load stamp (shown for any account); Retained is the credential journal.
+	Deleted     bool
+	DeletedAt   string
+	DeletedName string
+	LastLoginAt string
+	LastLoginIP string
+	Retained    []RetainedRow
 	// FlaggedHighRateAt is the pre-formatted soft high-rate marker timestamp,
 	// empty for an unflagged account; the card shows it with the Clear action.
 	FlaggedHighRateAt string
@@ -161,8 +173,14 @@ type UserDetailView struct {
 	HasStats     bool
 	Stats        StatsRow
 	Identities   []IdentityRow
+	// HasEmail gates the "Erase email" action; set when the account carries an email identity.
+	HasEmail bool
 	Games    []GameRow
+	// TelegramID and VKID are the account's platform external ids (empty when absent).
+	// TelegramID gates the "Send Telegram message" operator action; VKID surfaces the VK
+	// user id with a link to the VK profile (there is no VK messaging to drive).
 	TelegramID       string
+	VKID             string
 	ConnectorEnabled bool
 	// MoveChart is the pre-rendered inline SVG of the account's per-move-number think
 	// time (min/mean/max), empty when the account has no timed move.
@@ -230,6 +248,17 @@ type IdentityRow struct {
 	CreatedAt  string
 }
 
+// RetainedRow is one credential in the account-deletion retention journal (the legal
+// dossier of detached credentials): what was detached, when, and why.
+type RetainedRow struct {
+	Kind       string
+	ExternalID string
+	Reason     string
+	Confirmed  bool
+	LinkedAt   string
+	DetachedAt string
+}
+
 // GameRow is one game row in a list.
 type GameRow struct {
 	ID        string
@@ -554,5 +583,17 @@ type FeedbackDetailView struct {
 	ReplyBody         string
 	RepliedAt         string
 	CreatedAt         string
+	// Version is the client app build the report was sent from (empty for rows that predate it).
+	Version string
+	// The Filed time is shown in three zones so the operator can tell what is certainly known from
+	// what is merely defaulted. CreatedAt is the authoritative UTC time. CreatedAtBrowser is that
+	// instant in the client's UTC offset detected at submit (BrowserTZ its "±HH:MM" label), empty
+	// when the client reported none (an older build). CreatedAtUser is that instant in the sender's
+	// saved profile zone (UserTZ its label), empty when the account has no zone beyond the UTC
+	// default — the template then shows "N/A" so the missing datum is explicit.
+	CreatedAtBrowser string
+	BrowserTZ        string
+	CreatedAtUser    string
+	UserTZ           string
 	Banned           bool
 }

backend/internal/config/config.go

@@ -4,6 +4,7 @@ package config
 
 import (
 	"fmt"
+	"net/url"
 	"os"
 	"strconv"
 	"time"
@@ -42,6 +43,12 @@ type Config struct {
 	// SMTP configures the email relay used for confirm-codes. An empty Host
 	// selects the development log mailer (the code is logged, not sent).
 	SMTP account.SMTPConfig
+	// PublicBaseURL is the canonical public origin (scheme + host, e.g.
+	// https://erudit-game.ru) used to build absolute links in outgoing email — the
+	// confirm deeplink and the footer landing link. It is deliberately not derived
+	// from a request Host header, which would let an attacker inject a phishing link
+	// into the email. Required whenever an SMTP relay is configured.
+	PublicBaseURL string
 	// ConnectorAddr is the gRPC address of the Telegram platform connector
 	// side-service, used by the admin console to send operator broadcasts. Empty
 	// disables broadcasts (the admin broadcast actions report "not configured").
@@ -51,6 +58,12 @@ type Config struct {
 	// GuestRetention is the account age past which an unused guest (no game seat)
 	// is eligible for deletion by the reaper.
 	GuestRetention time.Duration
+	// ExportSignKey signs the finished-game export download URLs. Empty leaves
+	// the export-URL endpoints disabled (503 on mint, 404 on download).
+	ExportSignKey string
+	// RendererURL is the base URL of the internal image-render sidecar (e.g.
+	// http://renderer:8090). Empty disables the PNG export artifact.
+	RendererURL string
 }
 
 // Defaults applied when the corresponding environment variable is unset.
@@ -135,6 +148,9 @@ func Load() (Config, error) {
 		Username:  os.Getenv("BACKEND_SMTP_USERNAME"),
 		Password:  os.Getenv("BACKEND_SMTP_PASSWORD"),
 		From:      envOr("BACKEND_SMTP_FROM", "no-reply@localhost"),
+		TLS:       os.Getenv("BACKEND_SMTP_TLS"),
+		AdminFrom: os.Getenv("BACKEND_SMTP_ADMIN_FROM"),
+		AdminTo:   os.Getenv("BACKEND_ADMIN_EMAIL"),
 	}
 
 	c := Config{
@@ -148,9 +164,12 @@ func Load() (Config, error) {
 		Robot:             rb,
 		RateWatch:         rw,
 		SMTP:              smtp,
+		PublicBaseURL:     os.Getenv("BACKEND_PUBLIC_BASE_URL"),
 		ConnectorAddr:     os.Getenv("BACKEND_CONNECTOR_ADDR"),
 		GuestReapInterval: guestReapInterval,
 		GuestRetention:    guestRetention,
+		ExportSignKey:     os.Getenv("BACKEND_EXPORT_SIGN_KEY"),
+		RendererURL:       os.Getenv("BACKEND_RENDERER_URL"),
 	}
 	if err := c.validate(); err != nil {
 		return Config{}, err
@@ -195,6 +214,14 @@ func (c Config) validate() error {
 	if c.GuestRetention <= 0 {
 		return fmt.Errorf("config: BACKEND_GUEST_RETENTION must be positive")
 	}
+	if c.SMTP.Host != "" {
+		if c.PublicBaseURL == "" {
+			return fmt.Errorf("config: BACKEND_PUBLIC_BASE_URL must be set when BACKEND_SMTP_HOST is configured")
+		}
+		if u, err := url.Parse(c.PublicBaseURL); err != nil || u.Scheme == "" || u.Host == "" {
+			return fmt.Errorf("config: BACKEND_PUBLIC_BASE_URL %q must be an absolute URL (scheme://host)", c.PublicBaseURL)
+		}
+	}
 	return nil
 }
 

backend/internal/engine/registry.go

@@ -21,11 +21,13 @@ var dictFiles = map[Variant]string{
 	VariantErudit:          "ru_erudit.dawg",
 }
 
-// entry is one resident dictionary: the loaded finder and the solver built over
+// entry is one resident dictionary: the loaded finder, the solver built over it
-// it. The finder is retained so Close can release it.
+// and the file it was loaded from. The finder is retained so Close can release
+// it; path is retained so the raw bytes can be re-read for the client download.
 type entry struct {
 	finder dawg.Finder
 	solver *scrabble.Solver
+	path   string
 }
 
 // Registry holds the dictionaries resident in memory, addressed by variant and
@@ -130,7 +132,7 @@ func (r *Registry) Load(v Variant, version, dir string) error {
 	if old, ok := r.entries[v][version]; ok {
 		_ = old.finder.Close()
 	}
-	r.entries[v][version] = entry{finder: finder, solver: scrabble.NewSolver(rs, finder)}
+	r.entries[v][version] = entry{finder: finder, solver: scrabble.NewSolver(rs, finder), path: path}
 	r.latest[v] = version
 	return nil
 }
@@ -202,6 +204,30 @@ func (r *Registry) Versions(v Variant) []string {
 	return versions
 }
 
+// DictBytes returns the raw serialized DAWG for the (variant, version) pair,
+// re-read from the file it was loaded from — the same immutable bytes the solver
+// holds. It backs the client-side dictionary download for the local move
+// preview. It returns ErrUnknownVariant or ErrUnknownVersion when that dictionary
+// is not resident, and wraps any read error. The file is read outside the lock.
+func (r *Registry) DictBytes(v Variant, version string) ([]byte, error) {
+	r.mu.RLock()
+	versions, ok := r.entries[v]
+	if !ok {
+		r.mu.RUnlock()
+		return nil, fmt.Errorf("%w: %s", ErrUnknownVariant, v)
+	}
+	e, ok := versions[version]
+	r.mu.RUnlock()
+	if !ok {
+		return nil, fmt.Errorf("%w: %s/%s", ErrUnknownVersion, v, version)
+	}
+	data, err := os.ReadFile(e.path)
+	if err != nil {
+		return nil, fmt.Errorf("engine: read %s/%s dictionary bytes from %s: %w", v, version, e.path, err)
+	}
+	return data, nil
+}
+
 // Lookup reports whether word is present in the (variant, version) dictionary,
 // backing the unlimited word-check tool. It returns ErrUnknownVariant or
 // ErrUnknownVersion when that dictionary is not resident, and an error when word

backend/internal/feedback/service.go

@@ -72,7 +72,7 @@ func (svc *Service) SetNotifier(p notify.Publisher) {
 // validates the body (non-empty, within the rune limit) and the optional
 // attachment (size and extension allow-list). senderIP is the gateway-forwarded
 // client IP (validated); channel is the submitting platform.
-func (svc *Service) Submit(ctx context.Context, accountID uuid.UUID, body string, attachment []byte, attachmentName, channel, senderIP string) error {
+func (svc *Service) Submit(ctx context.Context, accountID uuid.UUID, body string, attachment []byte, attachmentName, channel, version, browserTZ, senderIP string) error {
 	acc, err := svc.accounts.GetByID(ctx, accountID)
 	if err != nil {
 		return err
@@ -112,9 +112,10 @@ func (svc *Service) Submit(ctx context.Context, accountID uuid.UUID, body string
 		attachmentName = "" // a name without bytes carries no attachment
 	}
 	ch := normalizeChannel(channel)
-	// Snapshot the sender's interface language at submit time (acc is already loaded
+	// Snapshot the sender's interface language, the client app version and the client's
-	// for the guest check) so the operator later sees the state as it was.
+	// detected UTC offset at submit time (acc is already loaded for the guest check) so the
-	_, err = svc.store.Insert(ctx, accountID, body, attachment, attachmentName, ch, acc.PreferredLanguage, parseIP(senderIP))
+	// operator later sees the state as it was.
+	_, err = svc.store.Insert(ctx, accountID, body, attachment, attachmentName, ch, acc.PreferredLanguage, version, browserTZ, parseIP(senderIP))
 	return err
 }
 
@@ -194,6 +195,11 @@ func (svc *Service) CountUnread(ctx context.Context) (int, error) {
 	return svc.store.CountUnread(ctx)
 }
 
+// CountSince counts feedback created after since, for the operator alert worker.
+func (svc *Service) CountSince(ctx context.Context, since time.Time) (int, error) {
+	return svc.store.CountSince(ctx, since)
+}
+
 // Attachment returns a message's file name and bytes, reporting false when absent.
 func (svc *Service) Attachment(ctx context.Context, id uuid.UUID) (string, []byte, bool, error) {
 	return svc.store.Attachment(ctx, id)

backend/internal/feedback/store.go

@@ -34,10 +34,10 @@ func NewStore(db *sql.DB) *Store {
 
 // Insert stores one feedback message from accountID and returns its id. attachment
 // is the raw file bytes (nil for none); attachmentName, ip and a non-default
-// channel are stored as given. lang (the sender's interface language) is a snapshot
+// channel are stored as given. lang (interface language), version (client app build) and
-// taken now, so the operator later sees the state at submit time. created_at defaults
+// browserTZ (the client's detected "±HH:MM" UTC offset) are snapshots taken now, so the operator
-// to now() in the database.
+// later sees the state at submit time. created_at defaults to now() in the database.
-func (s *Store) Insert(ctx context.Context, accountID uuid.UUID, body string, attachment []byte, attachmentName, channel, lang string, ip *string) (uuid.UUID, error) {
+func (s *Store) Insert(ctx context.Context, accountID uuid.UUID, body string, attachment []byte, attachmentName, channel, lang, version, browserTZ string, ip *string) (uuid.UUID, error) {
 	id, err := uuid.NewV7()
 	if err != nil {
 		return uuid.Nil, fmt.Errorf("feedback: new message id: %w", err)
@@ -48,9 +48,9 @@ func (s *Store) Insert(ctx context.Context, accountID uuid.UUID, body string, at
 	}
 	if _, err := s.db.ExecContext(ctx,
 		`INSERT INTO backend.feedback_messages
-		   (message_id, account_id, body, attachment, attachment_name, channel, lang, sender_ip)
+		   (message_id, account_id, body, attachment, attachment_name, channel, lang, app_version, browser_tz, sender_ip)
-		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`,
+		 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)`,
-		id, accountID, body, att, nullStr(attachmentName), channel, nullStr(lang), ip); err != nil {
+		id, accountID, body, att, nullStr(attachmentName), channel, nullStr(lang), nullStr(version), nullStr(browserTZ), ip); err != nil {
 		return uuid.Nil, fmt.Errorf("feedback: insert: %w", err)
 	}
 	return id, nil
@@ -229,6 +229,14 @@ type AdminMessage struct {
 	Channel    string
 	// Lang is the sender's interface language, snapshotted at submit time.
 	Lang string
+	// Version is the client app build the report was sent from, snapshotted at submit time.
+	Version string
+	// BrowserTZ is the client's detected "±HH:MM" UTC offset at submit time, snapshotted so the
+	// filed time can be shown in the sender's browser-local zone even before they save a profile.
+	BrowserTZ string
+	// TimeZone is the sender account's stored zone ("±HH:MM" offset, IANA name, or ""), for
+	// rendering CreatedAt in the sender's own configured time alongside UTC.
+	TimeZone       string
 	SenderIP       string
 	HasAttachment  bool
 	AttachmentName string
@@ -343,7 +351,7 @@ func (s *Store) AdminGet(ctx context.Context, id uuid.UUID) (AdminMessage, error
 	var m AdminMessage
 	var repliedAt sql.NullTime
 	q := `SELECT m.message_id, m.account_id, a.display_name, ` + feedbackSource + ` AS source, m.body, m.channel,
-		COALESCE(m.lang, ''),
+		COALESCE(m.lang, ''), COALESCE(m.app_version, ''), COALESCE(m.browser_tz, ''), a.time_zone,
 		COALESCE(m.sender_ip, ''), (m.attachment IS NOT NULL), COALESCE(m.attachment_name, ''),
 		(m.read_at IS NOT NULL), (m.archived_at IS NOT NULL), (m.reply_body IS NOT NULL),
 		COALESCE(m.reply_body, ''), m.replied_at, m.created_at
@@ -352,7 +360,7 @@ func (s *Store) AdminGet(ctx context.Context, id uuid.UUID) (AdminMessage, error
 	WHERE m.message_id = $1`
 	err := s.db.QueryRowContext(ctx, q, id).Scan(
 		&m.ID, &m.AccountID, &m.SenderName, &m.Source, &m.Body, &m.Channel,
-		&m.Lang,
+		&m.Lang, &m.Version, &m.BrowserTZ, &m.TimeZone,
 		&m.SenderIP, &m.HasAttachment, &m.AttachmentName,
 		&m.Read, &m.Archived, &m.Replied, &m.ReplyBody, &repliedAt, &m.CreatedAt)
 	if errors.Is(err, sql.ErrNoRows) {
@@ -378,3 +386,15 @@ func (s *Store) CountUnread(ctx context.Context) (int, error) {
 	}
 	return n, nil
 }
+
+// CountSince counts feedback messages created strictly after since — the operator alert
+// worker's "new since the last check" signal.
+func (s *Store) CountSince(ctx context.Context, since time.Time) (int, error) {
+	var n int
+	if err := s.db.QueryRowContext(ctx,
+		`SELECT COUNT(*) FROM backend.feedback_messages WHERE created_at > $1`, since,
+	).Scan(&n); err != nil {
+		return 0, fmt.Errorf("feedback: count since: %w", err)
+	}
+	return n, nil
+}

backend/internal/game/service.go

@@ -54,6 +54,12 @@ type Service struct {
 	// have committed a move (a nudge answered by moving stops counting as unread). It is
 	// best-effort and kept as a func so the game package never imports the social package.
 	clearNudges func(ctx context.Context, gameID, accountID uuid.UUID) error
+	// expireNudges, when set, marks every pending nudge in a game read once the game
+	// finishes (the nudge badge is stale on a completed game). Unlike clearNudges it is
+	// keyed by game alone — it clears all seats' nudges, not one mover's — and runs on
+	// every completion path through commit. Best-effort; a func so the game package never
+	// imports the social package.
+	expireNudges func(ctx context.Context, gameID uuid.UUID) error
 	metrics      *gameMetrics
 	log          *zap.Logger
 }
@@ -107,6 +113,15 @@ func (svc *Service) SetNudgeClearer(fn func(ctx context.Context, gameID, account
 	svc.clearNudges = fn
 }
 
+// SetNudgeExpirer installs the hook that marks every pending nudge in a game read once the
+// game finishes, on any completion path (a closing move, a resignation, a turn-timeout or a
+// forfeit). It must be called during startup wiring; the default (nil) leaves a finished
+// game's nudges to expire only when a recipient opens the move history or chat. The social
+// package wires its ExpireNudges here. Chat messages are deliberately left unread.
+func (svc *Service) SetNudgeExpirer(fn func(ctx context.Context, gameID uuid.UUID) error) {
+	svc.expireNudges = fn
+}
+
 // SetFirstMoveEntropy overrides the entropy source for the first-move draw
 // (docs/ARCHITECTURE.md §6). It must be called during wiring or test setup before any
 // game is created; the production default is crypto/rand and is never overridden.
@@ -699,6 +714,16 @@ func (svc *Service) commit(ctx context.Context, gameID uuid.UUID, g *engine.Game
 	}
 	if c.finished {
 		svc.cache.remove(gameID)
+		// A finished game's nudges are stale, so clear them all here — every completion path
+		// funnels through commit (a closing move, a resignation, a forfeit or a turn-timeout),
+		// and only the move path also clears the mover's nudge on its own. Best-effort like
+		// clearNudges: the finish has committed, so a cleanup failure is logged, not surfaced.
+		// ExpireNudges leaves chat messages unread.
+		if svc.expireNudges != nil {
+			if err := svc.expireNudges(ctx, gameID); err != nil {
+				svc.log.Warn("expire nudges on game finish", zap.Error(err))
+			}
+		}
 	}
 	post, err := svc.store.GetGame(ctx, gameID)
 	if err != nil {
@@ -983,6 +1008,12 @@ func (svc *Service) CountComplaints(ctx context.Context, status string) (int, er
 	return svc.store.CountComplaints(ctx, status)
 }
 
+// CountComplaintsSince counts word complaints filed after since, for the operator alert
+// worker.
+func (svc *Service) CountComplaintsSince(ctx context.Context, since time.Time) (int, error) {
+	return svc.store.CountComplaintsSince(ctx, since)
+}
+
 // ResolveComplaint closes a complaint with an operator disposition (reject /
 // accept_add / accept_remove) and an optional note. An accepted complaint then
 // appears in DictionaryChanges until a rebuilt dictionary is loaded and the
@@ -1338,30 +1369,53 @@ func (svc *Service) SetupDraws(ctx context.Context, gameID uuid.UUID) ([]SetupDr
 	return svc.store.SetupDraws(ctx, gameID)
 }
 
-// ExportGCG renders a game as GCG text from the journal alone (no dictionary). It
+// ExportView returns a finished game with its journal and per-seat display names —
-// is allowed only on a finished game: exporting an in-progress game would leak the
+// the material every export artifact (the GCG text, the PNG render payload) is built
-// full move journal mid-play, so an active game yields ErrGameActive.
+// from. It is allowed only on a finished game: exporting an in-progress game would
-func (svc *Service) ExportGCG(ctx context.Context, gameID uuid.UUID) (string, error) {
+// leak the full move journal mid-play, so an active game yields ErrGameActive. In an
+// honest-AI game the robot seat is labelled "AI", not its pool name.
+func (svc *Service) ExportView(ctx context.Context, gameID uuid.UUID) (Game, []HistoryMove, []string, error) {
 	g, err := svc.store.GetGame(ctx, gameID)
 	if err != nil {
-		return "", err
+		return Game{}, nil, nil, err
 	}
 	if g.Status != StatusFinished {
-		return "", ErrGameActive
+		return Game{}, nil, nil, ErrGameActive
 	}
 	moves, err := svc.store.GetJournal(ctx, gameID)
 	if err != nil {
-		return "", err
+		return Game{}, nil, nil, err
 	}
 	names := svc.seatNames(ctx, g)
 	if g.VsAI {
-		// Label the robot seat "AI" in an honest-AI game's export, not its pool name.
 		for _, s := range g.Seats {
 			if robot, err := svc.accounts.IsRobot(ctx, s.AccountID); err == nil && robot {
 				names[s.Seat] = aiPlayerName
 			}
 		}
 	}
+	return g, moves, names, nil
+}
+
+// EnsureExportable reports whether a game may be exported (it exists and is
+// finished) without loading the journal — the export-URL mint check.
+func (svc *Service) EnsureExportable(ctx context.Context, gameID uuid.UUID) error {
+	g, err := svc.store.GetGame(ctx, gameID)
+	if err != nil {
+		return err
+	}
+	if g.Status != StatusFinished {
+		return ErrGameActive
+	}
+	return nil
+}
+
+// ExportGCG renders a game as GCG text from the journal alone (no dictionary).
+func (svc *Service) ExportGCG(ctx context.Context, gameID uuid.UUID) (string, error) {
+	g, moves, names, err := svc.ExportView(ctx, gameID)
+	if err != nil {
+		return "", err
+	}
 	return writeGCG(g, names, moves), nil
 }
 
@@ -1440,13 +1494,24 @@ func (svc *Service) voidGame(ctx context.Context, pre Game, g *engine.Game) erro
 	if err != nil {
 		return err
 	}
-	return svc.store.VoidGame(ctx, voidCommit{
+	if err := svc.store.VoidGame(ctx, voidCommit{
 		gameID:    pre.ID,
 		endReason: g.Reason().String(),
 		scores:    scores,
 		now:       svc.clock(),
 		stats:     buildStats(g, statSeats),
-	})
+	}); err != nil {
+		return err
+	}
+	// A voided game is finished (as a draw) but bypasses commit, so clear its now-stale nudges
+	// here too. Best-effort, like the commit path: the void has persisted, so a cleanup failure
+	// is logged, not surfaced.
+	if svc.expireNudges != nil {
+		if err := svc.expireNudges(ctx, pre.ID); err != nil {
+			svc.log.Warn("expire nudges on voided game", zap.Error(err))
+		}
+	}
+	return nil
 }
 
 // replayMove re-applies one journalled move to g through the decoded engine API.
@@ -1613,6 +1678,14 @@ func (svc *Service) lookupWord(variant engine.Variant, version, word string) (bo
 	return present, nil
 }
 
+// DictBytes returns the raw serialized dictionary for the (variant, version) pair
+// from the registry, backing the client-side dictionary download used by the
+// local move preview. It surfaces engine.ErrUnknownVariant /
+// engine.ErrUnknownVersion when that dictionary is not resident.
+func (svc *Service) DictBytes(variant engine.Variant, version string) ([]byte, error) {
+	return svc.registry.DictBytes(variant, version)
+}
+
 // hintsRemaining is a player's remaining hint budget: the unspent per-game
 // allowance plus the profile wallet.
 func hintsRemaining(allowance, used, wallet int) int {

backend/internal/game/store.go

@@ -1040,6 +1040,19 @@ func (s *Store) CountComplaints(ctx context.Context, status string) (int, error)
 	return int(dest.Count), nil
 }
 
+// CountComplaintsSince counts word complaints filed strictly after since — the operator
+// alert worker's "new since the last check" signal.
+func (s *Store) CountComplaintsSince(ctx context.Context, since time.Time) (int, error) {
+	stmt := postgres.SELECT(postgres.COUNT(table.Complaints.ComplaintID).AS("count")).
+		FROM(table.Complaints).
+		WHERE(table.Complaints.CreatedAt.GT(postgres.TimestampzT(since)))
+	var dest struct{ Count int64 }
+	if err := stmt.QueryContext(ctx, s.db, &dest); err != nil {
+		return 0, fmt.Errorf("game: count complaints since: %w", err)
+	}
+	return int(dest.Count), nil
+}
+
 // ActiveGames returns the turn clocks of every in-progress game; the sweeper
 // filters them against the per-move deadline and the player's away window.
 func (s *Store) ActiveGames(ctx context.Context) ([]activeGame, error) {

backend/internal/inttest/account_test.go

@@ -110,15 +110,15 @@ func identityConfirmed(t *testing.T, kind, externalID string) bool {
 }
 
 // TestProvisionTelegramSeedsNewAccountOnly checks that Telegram first contact
-// seeds the new account's language and display name from the launch fields,
+// seeds the new account's language, display name and time zone from the launch
-// defaults the in-app-only flag on, and never overwrites an existing account on a
+// fields / detected offset, defaults the in-app-only flag on, and never overwrites
-// later login (language seeding).
+// an existing account on a later login (language and zone seeding).
 func TestProvisionTelegramSeedsNewAccountOnly(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
 	ext := "tg-" + uuid.NewString()
 
-	acc, created, err := store.ProvisionTelegram(ctx, ext, "ru-RU", "thehandle", "Иван")
+	acc, created, err := store.ProvisionTelegram(ctx, ext, "ru-RU", "thehandle", "Иван", "+03:00")
 	if err != nil {
 		t.Fatalf("provision telegram: %v", err)
 	}
@@ -131,12 +131,15 @@ func TestProvisionTelegramSeedsNewAccountOnly(t *testing.T) {
 	if acc.DisplayName != "Иван" {
 		t.Errorf("DisplayName = %q, want Иван", acc.DisplayName)
 	}
+	if acc.TimeZone != "+03:00" {
+		t.Errorf("TimeZone = %q, want the seeded +03:00", acc.TimeZone)
+	}
 	if !acc.NotificationsInAppOnly {
 		t.Error("NotificationsInAppOnly should default to true")
 	}
 
 	// A later login with different fields returns the same account, unchanged.
-	again, created, err := store.ProvisionTelegram(ctx, ext, "en", "other", "Other")
+	again, created, err := store.ProvisionTelegram(ctx, ext, "en", "other", "Other", "+09:00")
 	if err != nil {
 		t.Fatalf("re-provision telegram: %v", err)
 	}
@@ -146,8 +149,100 @@ func TestProvisionTelegramSeedsNewAccountOnly(t *testing.T) {
 	if again.ID != acc.ID {
 		t.Errorf("re-provision id = %s, want %s", again.ID, acc.ID)
 	}
-	if again.PreferredLanguage != "ru" || again.DisplayName != "Иван" {
+	if again.PreferredLanguage != "ru" || again.DisplayName != "Иван" || again.TimeZone != "+03:00" {
-		t.Errorf("existing account overwritten: lang=%q name=%q", again.PreferredLanguage, again.DisplayName)
+		t.Errorf("existing account overwritten: lang=%q name=%q tz=%q", again.PreferredLanguage, again.DisplayName, again.TimeZone)
+	}
+}
+
+// TestProvisionVKSeedsNewAccountOnly checks VK first contact seeds the new account's
+// language, display name and time zone from the launch fields / detected offset, records
+// the vk identity as confirmed (a platform identity), and never overwrites an existing
+// account on a later launch. It also exercises the widened identities.kind CHECK — a
+// 'vk' row must insert.
+func TestProvisionVKSeedsNewAccountOnly(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	ext := "vk-" + uuid.NewString()
+
+	acc, created, err := store.ProvisionVK(ctx, ext, "ru", "Иван Петров", "+03:00")
+	if err != nil {
+		t.Fatalf("provision vk: %v", err)
+	}
+	if !created {
+		t.Error("created = false on first contact, want true")
+	}
+	if acc.PreferredLanguage != "ru" {
+		t.Errorf("PreferredLanguage = %q, want ru", acc.PreferredLanguage)
+	}
+	if acc.DisplayName != "Иван Петров" {
+		t.Errorf("DisplayName = %q, want Иван Петров", acc.DisplayName)
+	}
+	if acc.TimeZone != "+03:00" {
+		t.Errorf("TimeZone = %q, want the seeded +03:00", acc.TimeZone)
+	}
+	// A VK identity is a platform identity: confirmed on insert.
+	if !identityConfirmed(t, account.KindVK, ext) {
+		t.Error("vk identity must be confirmed")
+	}
+
+	// A later launch with different fields returns the same account, unchanged.
+	again, created, err := store.ProvisionVK(ctx, ext, "en", "Other Name", "+09:00")
+	if err != nil {
+		t.Fatalf("re-provision vk: %v", err)
+	}
+	if created {
+		t.Error("created = true on a repeat launch, want false")
+	}
+	if again.ID != acc.ID {
+		t.Errorf("re-provision id = %s, want %s", again.ID, acc.ID)
+	}
+	if again.PreferredLanguage != "ru" || again.DisplayName != "Иван Петров" || again.TimeZone != "+03:00" {
+		t.Errorf("existing account overwritten: lang=%q name=%q tz=%q", again.PreferredLanguage, again.DisplayName, again.TimeZone)
+	}
+}
+
+// TestProvisionSeedsTimeZone checks the create-time time-zone seed across paths: a
+// valid detected offset is stored verbatim (even "+00:00", which is deliberately
+// distinct from the unset "UTC" default), a guest is seeded the same way, and a
+// missing or malformed offset falls back to the "UTC" column default rather than
+// being guessed at.
+func TestProvisionSeedsTimeZone(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+
+	// A detected zero offset is written as "+00:00" — we record that the zone was
+	// detected (and equals UTC), distinct from the "UTC" default meaning "unknown".
+	utcDetected, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Zero", "+00:00")
+	if err != nil {
+		t.Fatalf("provision telegram +00:00: %v", err)
+	}
+	if utcDetected.TimeZone != "+00:00" {
+		t.Errorf("TimeZone = %q, want the seeded +00:00", utcDetected.TimeZone)
+	}
+
+	// A malformed offset is dropped: the account keeps the UTC default.
+	bad, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Bad", "not-a-zone")
+	if err != nil {
+		t.Fatalf("provision telegram bad tz: %v", err)
+	}
+	if bad.TimeZone != "UTC" {
+		t.Errorf("TimeZone = %q, want UTC fallback for a malformed offset", bad.TimeZone)
+	}
+
+	// A guest is seeded its detected offset; an empty one keeps the UTC default.
+	guest, err := store.ProvisionGuest(ctx, "-05:30")
+	if err != nil {
+		t.Fatalf("provision guest: %v", err)
+	}
+	if guest.TimeZone != "-05:30" {
+		t.Errorf("guest TimeZone = %q, want the seeded -05:30", guest.TimeZone)
+	}
+	plainGuest, err := store.ProvisionGuest(ctx, "")
+	if err != nil {
+		t.Fatalf("provision plain guest: %v", err)
+	}
+	if plainGuest.TimeZone != "UTC" {
+		t.Errorf("plain guest TimeZone = %q, want UTC default", plainGuest.TimeZone)
 	}
 }
 
@@ -156,7 +251,7 @@ func TestProvisionTelegramSeedsNewAccountOnly(t *testing.T) {
 // language CHECK.
 func TestProvisionTelegramUnknownLanguageDefaults(t *testing.T) {
 	ctx := context.Background()
-	acc, _, err := account.NewStore(testDB).ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "fr", "", "")
+	acc, _, err := account.NewStore(testDB).ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "fr", "", "", "")
 	if err != nil {
 		t.Fatalf("provision telegram: %v", err)
 	}
@@ -172,7 +267,7 @@ func TestProvisionTelegramUnknownLanguageDefaults(t *testing.T) {
 func TestHighRateFlagRoundTrip(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
-	acc, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Player")
+	acc, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Player", "")
 	if err != nil {
 		t.Fatalf("provision telegram: %v", err)
 	}
@@ -228,7 +323,7 @@ func TestIdentityExternalID(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
 	ext := "tg-" + uuid.NewString()
-	acc, _, err := store.ProvisionTelegram(ctx, ext, "en", "", "Tg User")
+	acc, _, err := store.ProvisionTelegram(ctx, ext, "en", "", "Tg User", "")
 	if err != nil {
 		t.Fatalf("provision telegram: %v", err)
 	}
@@ -253,7 +348,7 @@ func TestIdentityExternalID(t *testing.T) {
 func TestNotificationsInAppOnlyRoundTrip(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
-	acc, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Player")
+	acc, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Player", "")
 	if err != nil {
 		t.Fatalf("provision telegram: %v", err)
 	}

backend/internal/inttest/admin_test.go

@@ -222,7 +222,7 @@ func TestConsoleGameDetailRobotSchedule(t *testing.T) {
 func TestConsoleThrottledViewAndFlagClear(t *testing.T) {
 	ctx := context.Background()
 	accounts := account.NewStore(testDB)
-	acc, _, err := accounts.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Throttled Player")
+	acc, _, err := accounts.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Throttled Player", "")
 	if err != nil {
 		t.Fatalf("provision: %v", err)
 	}

backend/internal/inttest/adminemail_test.go

@@ -0,0 +1,83 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/account"
+)
+
+// TestRemoveEmailIdentity erases an account's email identity but refuses when the
+// email is the account's only identity (which would leave it unreachable).
+func TestRemoveEmailIdentity(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+
+	// Email is the only identity → refuse.
+	solo, err := store.ProvisionEmail(ctx, "solo-"+uuid.NewString()+"@example.com", "", "en")
+	if err != nil {
+		t.Fatalf("provision email: %v", err)
+	}
+	if err := store.RemoveEmailIdentity(ctx, solo.ID); !errors.Is(err, account.ErrLastIdentity) {
+		t.Fatalf("remove last identity = %v, want ErrLastIdentity", err)
+	}
+
+	// Telegram + email → erase the email, keep Telegram.
+	tg, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision telegram: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, tg.ID, account.KindEmail, "dual-"+uuid.NewString()+"@example.com", true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+	if err := store.RemoveEmailIdentity(ctx, tg.ID); err != nil {
+		t.Fatalf("remove email: %v", err)
+	}
+	ids, err := store.Identities(ctx, tg.ID)
+	if err != nil {
+		t.Fatalf("identities: %v", err)
+	}
+	if len(ids) != 1 || ids[0].Kind != account.KindTelegram {
+		t.Errorf("identities after erase = %+v, want only telegram", ids)
+	}
+}
+
+// TestListUsersEmailExact matches accounts strictly (exactly) by their email identity.
+func TestListUsersEmailExact(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	email := "find-" + uuid.NewString() + "@example.com"
+	acc, err := store.ProvisionEmail(ctx, email, "", "en")
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+
+	items, err := store.ListUsers(ctx, account.UserFilter{EmailExact: email}, 50, 0)
+	if err != nil {
+		t.Fatalf("list: %v", err)
+	}
+	found := false
+	for _, it := range items {
+		if it.ID == acc.ID {
+			found = true
+		}
+	}
+	if !found {
+		t.Error("the exact email filter did not find the account")
+	}
+
+	other, err := store.ListUsers(ctx, account.UserFilter{EmailExact: "nope-" + uuid.NewString() + "@example.com"}, 50, 0)
+	if err != nil {
+		t.Fatalf("list (no match): %v", err)
+	}
+	for _, it := range other {
+		if it.ID == acc.ID {
+			t.Error("a non-matching email filter must not return the account")
+		}
+	}
+}

backend/internal/inttest/chat_access_test.go

@@ -55,7 +55,7 @@ func TestChatAccessResolver(t *testing.T) {
 	srv := server.New(":0", server.Deps{Logger: zaptest.NewLogger(t), DB: testDB, Accounts: accounts})
 
 	ext := "tg-" + uuid.NewString()
-	acc, _, err := accounts.ProvisionTelegram(ctx, ext, "en", "", "Chatter")
+	acc, _, err := accounts.ProvisionTelegram(ctx, ext, "en", "", "Chatter", "")
 	if err != nil {
 		t.Fatalf("provision: %v", err)
 	}

backend/internal/inttest/chatread_test.go

@@ -138,6 +138,65 @@ func TestNudgeClearedByMove(t *testing.T) {
 	}
 }
 
+// TestGameCompletionExpiresNudgesKeepsChat checks that finishing a game by turn-timeout marks every
+// pending nudge in it read — the lobby's nudge badge is stale once the game is over — while leaving
+// real chat messages unread. It reproduces the reported bug: the timeout path commits the finish
+// directly, bypassing the move path's per-mover nudge clear, so without a completion-driven expiry
+// the awaited seat's nudge lingered as a badge on the finished game.
+func TestGameCompletionExpiresNudgesKeepsChat(t *testing.T) {
+	ctx := context.Background()
+	gameSvc := newGameService()
+	socialSvc := newSocialService()
+	gameSvc.SetNudgeExpirer(socialSvc.ExpireNudges)
+
+	seats := []uuid.UUID{provisionAccount(t), provisionAccount(t)}
+	g, err := gameSvc.Create(ctx, game.CreateParams{
+		Variant: engine.VariantEnglish, Seats: seats, TurnTimeout: time.Hour, Seed: openingSeed(t),
+	})
+	if err != nil {
+		t.Fatalf("create: %v", err)
+	}
+
+	// Seat 1 nudges the to-move seat 0 (the awaited player), and seat 0 posts a real chat message,
+	// which seat 1 then holds unread. So before the timeout each side has exactly one unread entry:
+	// seat 0 a nudge, seat 1 a message — letting HasUnread isolate each kind.
+	if _, err := socialSvc.Nudge(ctx, g.ID, seats[1]); err != nil {
+		t.Fatalf("nudge: %v", err)
+	}
+	if _, err := socialSvc.PostMessage(ctx, g.ID, seats[0], "good luck", ""); err != nil {
+		t.Fatalf("post message: %v", err)
+	}
+	if unread, _ := socialSvc.HasUnread(ctx, g.ID, seats[0]); !unread {
+		t.Fatal("seat 0 should hold the nudge unread before the timeout")
+	}
+	if unread, _ := socialSvc.HasUnread(ctx, g.ID, seats[1]); !unread {
+		t.Fatal("seat 1 should hold the message unread before the timeout")
+	}
+
+	// Age the turn past its deadline and time seat 0 out; an empty away window keeps this
+	// deterministic regardless of the wall clock. The sweep finishes the game through the direct
+	// commit path, never the move path.
+	backdate(t, g.ID, time.Now().UTC().Add(-2*time.Hour))
+	setAway(t, seats[0], "UTC", "00:00", "00:00")
+	if n, err := gameSvc.SweepTimeouts(ctx, time.Now().UTC()); err != nil || n < 1 {
+		t.Fatalf("sweep swept %d (err %v), want >= 1", n, err)
+	}
+	if status, reason := gameStatus(t, gameSvc, g.ID); status != game.StatusFinished || reason != "timeout" {
+		t.Fatalf("game not timed out: status %q reason %q", status, reason)
+	}
+
+	// The nudge is stale on a finished game and must be cleared; the chat message must survive.
+	if unread, _ := socialSvc.HasUnread(ctx, g.ID, seats[0]); unread {
+		t.Error("the nudge should be expired once the game has finished")
+	}
+	if unread, _ := socialSvc.HasUnread(ctx, g.ID, seats[1]); !unread {
+		t.Error("a real chat message must stay unread after the game finishes")
+	}
+	if msg, _ := socialSvc.HasUnreadMessage(ctx, g.ID, seats[1]); !msg {
+		t.Error("the chat message must remain flagged as an unread message after completion")
+	}
+}
+
 // TestChatToRobotIsBornRead checks a text message to a disguised robot opponent (a pooled
 // robot substituted into an ordinary, non-AI game) is born read: the robot never opens the
 // chat, so the message must not linger unread (skewing the count and the read metric).

backend/internal/inttest/delete_test.go

@@ -0,0 +1,322 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/account"
+	"scrabble/backend/internal/accountdelete"
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
+)
+
+// deletedFields reads a tombstoned account's retained real name and its deleted_at.
+func deletedFields(t *testing.T, accountID uuid.UUID) (name string, deletedAt sql.NullTime) {
+	t.Helper()
+	var dn sql.NullString
+	err := testDB.QueryRowContext(context.Background(),
+		"SELECT deleted_display_name, deleted_at FROM accounts WHERE account_id = $1", accountID).
+		Scan(&dn, &deletedAt)
+	if err != nil {
+		t.Fatalf("read deleted fields %s: %v", accountID, err)
+	}
+	return dn.String, deletedAt
+}
+
+// TestAnonymizeAndTombstone: deletion journals + frees the credentials, tombstones the
+// account, scrubs the live name while retaining the real one, and frees the creds for a
+// new account to reuse.
+func TestAnonymizeAndTombstone(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	deleter := accountdelete.NewDeleter(testDB)
+
+	acc, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "ru", "handle", "Иван", "+03:00")
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	email := "del-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, email, true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+	before, err := store.GetByID(ctx, acc.ID)
+	if err != nil {
+		t.Fatalf("load before: %v", err)
+	}
+
+	if err := deleter.AnonymizeAndTombstone(ctx, acc.ID); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+
+	// The live identities are gone.
+	if ids, err := store.Identities(ctx, acc.ID); err != nil || len(ids) != 0 {
+		t.Fatalf("identities after delete = %+v (err %v), want none", ids, err)
+	}
+	// Both credentials are journalled with reason=delete.
+	got := retainedRows(t, acc.ID)
+	if len(got) != 2 {
+		t.Fatalf("retained rows = %+v, want 2", got)
+	}
+	for _, r := range got {
+		if r.reason != "delete" {
+			t.Errorf("retained reason = %q, want delete", r.reason)
+		}
+	}
+	// The live name is scrubbed; the real one is retained; deleted_at is set.
+	after, err := store.GetByID(ctx, acc.ID)
+	if err != nil {
+		t.Fatalf("load after: %v", err)
+	}
+	if after.DisplayName != accountdelete.AnonymizedName {
+		t.Errorf("live display name = %q, want %q", after.DisplayName, accountdelete.AnonymizedName)
+	}
+	name, deletedAt := deletedFields(t, acc.ID)
+	if name != before.DisplayName {
+		t.Errorf("retained name = %q, want %q", name, before.DisplayName)
+	}
+	if !deletedAt.Valid || time.Since(deletedAt.Time) > time.Minute {
+		t.Errorf("deleted_at = %+v, want a recent timestamp", deletedAt)
+	}
+	// The credentials are free: a new account can claim the same email.
+	other, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Other", "")
+	if err != nil {
+		t.Fatalf("provision other: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, other.ID, account.KindEmail, email, true); err != nil {
+		t.Fatalf("email should be free after deletion, got: %v", err)
+	}
+}
+
+// TestDeletionDossierReaders: after deletion the admin readers expose the credential
+// journal and the tombstone dossier.
+func TestDeletionDossierReaders(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	deleter := accountdelete.NewDeleter(testDB)
+
+	acc, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "ru", "handle", "Иван", "+03:00")
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, "dos-"+uuid.NewString()+"@example.com", true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+	if err := deleter.AnonymizeAndTombstone(ctx, acc.ID); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+
+	rets, err := store.RetainedIdentities(ctx, acc.ID)
+	if err != nil || len(rets) != 2 {
+		t.Fatalf("RetainedIdentities = (%+v, %v), want 2 rows", rets, err)
+	}
+	for _, r := range rets {
+		if r.Reason != "delete" {
+			t.Errorf("retained reason = %q, want delete", r.Reason)
+		}
+	}
+	info, err := store.DeletionInfo(ctx, acc.ID)
+	if err != nil {
+		t.Fatalf("DeletionInfo: %v", err)
+	}
+	if info.DeletedAt == nil {
+		t.Error("DeletionInfo.DeletedAt should be set")
+	}
+	if info.DeletedDisplayName != "Иван" {
+		t.Errorf("DeletionInfo.DeletedDisplayName = %q, want Иван", info.DeletedDisplayName)
+	}
+}
+
+// listHasID reports whether the user list contains accountID.
+func listHasID(items []account.UserListItem, id uuid.UUID) bool {
+	for _, it := range items {
+		if it.ID == id {
+			return true
+		}
+	}
+	return false
+}
+
+// TestUserListDeletedFilter: a tombstoned account is hidden from the default People list and
+// shown only under the Deleted scope.
+func TestUserListDeletedFilter(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	deleter := accountdelete.NewDeleter(testDB)
+
+	live, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "en", "", "Live", "")
+	if err != nil {
+		t.Fatalf("provision live: %v", err)
+	}
+	goneTg := "tg-" + uuid.NewString()
+	gone, _, err := store.ProvisionTelegram(ctx, goneTg, "en", "", "Gone", "")
+	if err != nil {
+		t.Fatalf("provision gone: %v", err)
+	}
+	goneEmail := "gone-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, gone.ID, account.KindEmail, goneEmail, true); err != nil {
+		t.Fatalf("attach gone email: %v", err)
+	}
+	if err := deleter.AnonymizeAndTombstone(ctx, gone.ID); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+
+	people, err := store.ListUsers(ctx, account.UserFilter{}, 5000, 0)
+	if err != nil {
+		t.Fatalf("list people: %v", err)
+	}
+	if listHasID(people, gone.ID) {
+		t.Error("a deleted account must not appear in the default People list")
+	}
+	if !listHasID(people, live.ID) {
+		t.Error("a live account must appear in the default People list")
+	}
+	deleted, err := store.ListUsers(ctx, account.UserFilter{Deleted: true}, 5000, 0)
+	if err != nil {
+		t.Fatalf("list deleted: %v", err)
+	}
+	if !listHasID(deleted, gone.ID) {
+		t.Error("a deleted account must appear in the Deleted list")
+	}
+	if listHasID(deleted, live.ID) {
+		t.Error("a live account must not appear in the Deleted list")
+	}
+
+	// A search spans both lists and reaches the retention journal: a deleted account is
+	// still found by the email and external id it held (both moved to retained_identities
+	// on deletion, out of the live identities table).
+	byEmail, err := store.ListUsers(ctx, account.UserFilter{EmailExact: goneEmail}, 5000, 0)
+	if err != nil {
+		t.Fatalf("search by email: %v", err)
+	}
+	if !listHasID(byEmail, gone.ID) {
+		t.Error("a deleted account must be found by the email it held (retention journal)")
+	}
+	byExt, err := store.ListUsers(ctx, account.UserFilter{ExternalIDMask: goneTg}, 5000, 0)
+	if err != nil {
+		t.Fatalf("search by external id: %v", err)
+	}
+	if !listHasID(byExt, gone.ID) {
+		t.Error("a deleted account must be found by the external id it held (retention journal)")
+	}
+}
+
+// TestConfirmCodeClearsGuest: confirming an email on a guest via ConfirmCode promotes it to
+// a durable account (defence-in-depth — no confirmed-email path leaves is_guest set).
+func TestConfirmCodeClearsGuest(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	guest, err := store.ProvisionGuest(ctx, "")
+	if err != nil {
+		t.Fatalf("provision guest: %v", err)
+	}
+	email := "cc-" + uuid.NewString() + "@example.com"
+	if err := svc.RequestCode(ctx, guest.ID, email); err != nil {
+		t.Fatalf("request code: %v", err)
+	}
+	if _, err := svc.ConfirmCode(ctx, guest.ID, email, sixDigit.FindString(mailer.lastBody)); err != nil {
+		t.Fatalf("confirm code: %v", err)
+	}
+	after, err := store.GetByID(ctx, guest.ID)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	if after.IsGuest {
+		t.Error("confirming an email must clear the guest flag")
+	}
+}
+
+// TestDropAllRobotGames drops the deletee's solo vs-AI game but keeps a game with a human
+// opponent.
+func TestDropAllRobotGames(t *testing.T) {
+	ctx := context.Background()
+	gsvc := newGameService()
+	robots := newRobotService(t, gsvc)
+	if err := robots.EnsurePool(ctx); err != nil {
+		t.Fatalf("ensure pool: %v", err)
+	}
+	mm := newMatchmaker(t, robots, time.Minute, 0)
+	deleter := accountdelete.NewDeleter(testDB)
+
+	user := provisionAccount(t)
+	other := provisionAccount(t)
+
+	aiRes, err := mm.StartVsAI(ctx, user, engine.VariantEnglish, true)
+	if err != nil {
+		t.Fatalf("start vs AI: %v", err)
+	}
+	humanGame, err := gsvc.Create(ctx, game.CreateParams{
+		Variant: engine.VariantEnglish, Seats: []uuid.UUID{user, other}, TurnTimeout: time.Hour, Seed: 1,
+	})
+	if err != nil {
+		t.Fatalf("create human game: %v", err)
+	}
+
+	n, err := deleter.DropAllRobotGames(ctx, user)
+	if err != nil {
+		t.Fatalf("drop: %v", err)
+	}
+	if n != 1 {
+		t.Fatalf("dropped %d games, want 1 (the vs-AI game)", n)
+	}
+	if _, err := gsvc.GameByID(ctx, aiRes.Game.ID); err == nil {
+		t.Error("the vs-AI game should be dropped")
+	}
+	if _, err := gsvc.GameByID(ctx, humanGame.ID); err != nil {
+		t.Errorf("the human game should be kept, got: %v", err)
+	}
+}
+
+// TestDeleteStepUpEmail: an email account's delete code verifies (wrong code rejected, no
+// deeplink in the mail); a platform-only account has no email and cannot request a code.
+func TestDeleteStepUpEmail(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, "del-"+uuid.NewString()+"@example.com", true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+	if has, err := svc.HasEmail(ctx, acc.ID); err != nil || !has {
+		t.Fatalf("HasEmail = (%v, %v), want true", has, err)
+	}
+	if err := svc.RequestDeleteCode(ctx, acc.ID); err != nil {
+		t.Fatalf("request delete code: %v", err)
+	}
+	if strings.Contains(mailer.lastBody, "/confirm/") {
+		t.Error("a delete email must not carry a one-tap deeplink")
+	}
+	code := sixDigit.FindString(mailer.lastBody)
+	if err := svc.VerifyDeleteCode(ctx, acc.ID, "000000"); err == nil {
+		t.Error("a wrong delete code must be rejected")
+	}
+	if err := svc.VerifyDeleteCode(ctx, acc.ID, code); err != nil {
+		t.Fatalf("verify correct delete code: %v", err)
+	}
+
+	noEmail, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision no-email: %v", err)
+	}
+	if has, _ := svc.HasEmail(ctx, noEmail.ID); has {
+		t.Error("HasEmail must be false for a platform-only account")
+	}
+	if err := svc.RequestDeleteCode(ctx, noEmail.ID); !errors.Is(err, account.ErrNoEmail) {
+		t.Errorf("request delete for no-email account = %v, want ErrNoEmail", err)
+	}
+}

backend/internal/inttest/email_test.go

@@ -19,8 +19,8 @@ import (
 // recover the confirm-code from the body.
 type capturingMailer struct{ lastBody string }
 
-func (m *capturingMailer) Send(_ context.Context, _, _, body string) error {
+func (m *capturingMailer) Send(_ context.Context, msg account.Message) error {
-	m.lastBody = body
+	m.lastBody = msg.Text
 	return nil
 }
 
@@ -32,7 +32,7 @@ func TestEmailConfirmFlow(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
 	mailer := &capturingMailer{}
-	svc := account.NewEmailService(store, mailer)
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 
 	acc := provisionAccount(t)
 	email := "user-" + uuid.NewString() + "@example.com"
@@ -67,7 +67,7 @@ func TestEmailAlreadyTakenByAnotherAccount(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
 	mailer := &capturingMailer{}
-	svc := account.NewEmailService(store, mailer)
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 
 	owner := provisionAccount(t)
 	email := "taken-" + uuid.NewString() + "@example.com"
@@ -89,7 +89,7 @@ func TestEmailCodeExpires(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
 	mailer := &capturingMailer{}
-	svc := account.NewEmailService(store, mailer)
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 
 	acc := provisionAccount(t)
 	email := "expire-" + uuid.NewString() + "@example.com"
@@ -111,7 +111,7 @@ func TestEmailTooManyAttempts(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
 	mailer := &capturingMailer{}
-	svc := account.NewEmailService(store, mailer)
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 
 	acc := provisionAccount(t)
 	email := "lock-" + uuid.NewString() + "@example.com"
@@ -203,10 +203,10 @@ func TestUpdateProfileOffsetTimezone(t *testing.T) {
 func TestEmailLoginFlow(t *testing.T) {
 	ctx := context.Background()
 	mailer := &capturingMailer{}
-	svc := account.NewEmailService(account.NewStore(testDB), mailer)
+	svc := account.NewEmailService(account.NewStore(testDB), mailer, "https://erudit-game.ru")
 	email := "login-" + uuid.NewString() + "@example.com"
 
-	accountID, err := svc.RequestLoginCode(ctx, email)
+	accountID, err := svc.RequestLoginCode(ctx, email, "+02:00", "en")
 	if err != nil {
 		t.Fatalf("request login code: %v", err)
 	}
@@ -225,12 +225,15 @@ func TestEmailLoginFlow(t *testing.T) {
 	if acc.IsGuest {
 		t.Error("an email account must be durable, not a guest")
 	}
+	if acc.TimeZone != "+02:00" {
+		t.Errorf("TimeZone = %q, want the +02:00 seeded at the request step", acc.TimeZone)
+	}
 	if !identityConfirmed(t, account.KindEmail, email) {
 		t.Error("the email identity must be confirmed after login")
 	}
 
 	// A second login for the same email is the returning user: same account.
-	if _, err := svc.RequestLoginCode(ctx, email); err != nil {
+	if _, err := svc.RequestLoginCode(ctx, email, "", "ru"); err != nil {
 		t.Fatalf("second request: %v", err)
 	}
 	acc2, err := svc.LoginWithCode(ctx, email, sixDigit.FindString(mailer.lastBody))
@@ -241,3 +244,182 @@ func TestEmailLoginFlow(t *testing.T) {
 		t.Errorf("returning login account = %s, want %s", acc2.ID, accountID)
 	}
 }
+
+// TestEmailLoginProvisionsGuestUntilConfirmed covers the squat fix: an email-login
+// account is a guest (reapable, so an abandoned never-confirmed login frees its
+// address) until the code is confirmed, which promotes it to a durable account.
+func TestEmailLoginProvisionsGuestUntilConfirmed(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+	email := "squat-" + uuid.NewString() + "@example.com"
+
+	id, err := svc.RequestLoginCode(ctx, email, "", "en")
+	if err != nil {
+		t.Fatalf("request login code: %v", err)
+	}
+	before, err := store.GetByID(ctx, id)
+	if err != nil {
+		t.Fatalf("get before confirm: %v", err)
+	}
+	if !before.IsGuest {
+		t.Error("an unconfirmed email-login account must be a guest so it is reapable")
+	}
+
+	if _, err := svc.LoginWithCode(ctx, email, sixDigit.FindString(mailer.lastBody)); err != nil {
+		t.Fatalf("login: %v", err)
+	}
+	after, err := store.GetByID(ctx, id)
+	if err != nil {
+		t.Fatalf("get after confirm: %v", err)
+	}
+	if after.IsGuest {
+		t.Error("confirming the login must clear the guest flag (promote to durable)")
+	}
+}
+
+// confirmToken extracts the one-tap deeplink token from the /app/#/confirm/<token> link
+// the branded email carries.
+var confirmToken = regexp.MustCompile(`/confirm/([A-Za-z0-9_-]+)`)
+
+func tokenFromMail(t *testing.T, body string) string {
+	t.Helper()
+	m := confirmToken.FindStringSubmatch(body)
+	if m == nil {
+		t.Fatalf("no confirm token in mail body %q", body)
+	}
+	return m[1]
+}
+
+// TestConfirmByTokenLogin: the one-tap deeplink token completes an email login,
+// clearing the guest flag.
+func TestConfirmByTokenLogin(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+	email := "tok-login-" + uuid.NewString() + "@example.com"
+
+	id, err := svc.RequestLoginCode(ctx, email, "", "en")
+	if err != nil {
+		t.Fatalf("request login: %v", err)
+	}
+	res, err := svc.ConfirmByToken(ctx, tokenFromMail(t, mailer.lastBody))
+	if err != nil {
+		t.Fatalf("confirm by token: %v", err)
+	}
+	if !res.IsLogin() || res.Account != id {
+		t.Fatalf("login result = %+v, want login for %s", res, id)
+	}
+	if !identityConfirmed(t, account.KindEmail, email) {
+		t.Error("email identity must be confirmed after the token login")
+	}
+	if acc, _ := store.GetByID(ctx, id); acc.IsGuest {
+		t.Error("the token login must clear the guest flag")
+	}
+}
+
+// TestConfirmByTokenLink: the token attaches a free email to the requesting account.
+func TestConfirmByTokenLink(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+	acc := provisionAccount(t)
+	email := "tok-link-" + uuid.NewString() + "@example.com"
+
+	if err := svc.RequestLinkCode(ctx, acc, email); err != nil {
+		t.Fatalf("request link: %v", err)
+	}
+	res, err := svc.ConfirmByToken(ctx, tokenFromMail(t, mailer.lastBody))
+	if err != nil {
+		t.Fatalf("confirm by token: %v", err)
+	}
+	if res.IsLogin() || res.NeedsMerge || res.Account != acc {
+		t.Fatalf("link result = %+v, want a plain link for %s", res, acc)
+	}
+	if !identityConfirmed(t, account.KindEmail, email) {
+		t.Error("email identity must be confirmed after the token link")
+	}
+}
+
+// TestConfirmByTokenLinkMerge: a token for an address owned by another account signals
+// a merge (leaving the token unconsumed for the interactive step).
+func TestConfirmByTokenLinkMerge(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+	email := "tok-merge-" + uuid.NewString() + "@example.com"
+
+	owner := provisionAccount(t)
+	if err := svc.RequestCode(ctx, owner, email); err != nil {
+		t.Fatalf("owner request: %v", err)
+	}
+	if _, err := svc.ConfirmCode(ctx, owner, email, sixDigit.FindString(mailer.lastBody)); err != nil {
+		t.Fatalf("owner confirm: %v", err)
+	}
+
+	other := provisionAccount(t)
+	if err := svc.RequestLinkCode(ctx, other, email); err != nil {
+		t.Fatalf("link request: %v", err)
+	}
+	res, err := svc.ConfirmByToken(ctx, tokenFromMail(t, mailer.lastBody))
+	if err != nil {
+		t.Fatalf("confirm by token: %v", err)
+	}
+	if !res.NeedsMerge || res.MergeOwner != owner {
+		t.Fatalf("merge result = %+v, want NeedsMerge with owner=%s", res, owner)
+	}
+}
+
+// TestEmailAccountSeedsDisplayName seeds a new email account's display name from the
+// email's local part, so an email login is not left nameless.
+func TestEmailAccountSeedsDisplayName(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	svc := account.NewEmailService(store, &capturingMailer{}, "https://erudit-game.ru")
+	local := "kaya-" + uuid.NewString()[:8]
+
+	id, err := svc.RequestLoginCode(ctx, local+"@example.com", "", "en")
+	if err != nil {
+		t.Fatalf("request login: %v", err)
+	}
+	acc, err := store.GetByID(ctx, id)
+	if err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	if acc.DisplayName != local {
+		t.Errorf("display name = %q, want the email local part %q", acc.DisplayName, local)
+	}
+}
+
+// TestConfirmByTokenLinkClearsGuest: binding an email to a guest via the deeplink
+// promotes the guest to a durable account (the deeplink path must match the
+// code-based link flow, which clears the guest flag).
+func TestConfirmByTokenLinkClearsGuest(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+	guest, err := store.ProvisionGuest(ctx, "")
+	if err != nil {
+		t.Fatalf("provision guest: %v", err)
+	}
+	email := "guest-link-" + uuid.NewString() + "@example.com"
+
+	if err := svc.RequestLinkCode(ctx, guest.ID, email); err != nil {
+		t.Fatalf("request link: %v", err)
+	}
+	if _, err := svc.ConfirmByToken(ctx, tokenFromMail(t, mailer.lastBody)); err != nil {
+		t.Fatalf("confirm by token: %v", err)
+	}
+	acc, err := store.GetByID(ctx, guest.ID)
+	if err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	if acc.IsGuest {
+		t.Error("linking an email via the deeplink must promote the guest to durable")
+	}
+}

backend/internal/inttest/feedback_test.go

@@ -38,7 +38,7 @@ func latestFeedbackID(t *testing.T, svc *feedback.Service, acc uuid.UUID) uuid.U
 func TestFeedbackGuestRejected(t *testing.T) {
 	svc := newFeedbackService()
 	guest := provisionGuest(t)
-	if err := svc.Submit(context.Background(), guest, "hi", nil, "", "web", "1.2.3.4"); !errors.Is(err, feedback.ErrGuestForbidden) {
+	if err := svc.Submit(context.Background(), guest, "hi", nil, "", "web", "v1", "+05:00", "1.2.3.4"); !errors.Is(err, feedback.ErrGuestForbidden) {
 		t.Fatalf("guest submit err = %v, want ErrGuestForbidden", err)
 	}
 }
@@ -48,11 +48,11 @@ func TestFeedbackSubmitGateAndReplyLifecycle(t *testing.T) {
 	svc := newFeedbackService()
 	acc := provisionAccount(t)
 
-	if err := svc.Submit(ctx, acc, "  please fix the board  ", []byte("PNGDATA"), "shot.png", "ios", "9.9.9.9"); err != nil {
+	if err := svc.Submit(ctx, acc, "  please fix the board  ", []byte("PNGDATA"), "shot.png", "ios", "v1.2.0", "+03:00", "9.9.9.9"); err != nil {
 		t.Fatalf("submit: %v", err)
 	}
 	// Anti-spam gate: a second message is refused while the first is unreviewed.
-	if err := svc.Submit(ctx, acc, "again", nil, "", "web", ""); !errors.Is(err, feedback.ErrPendingReview) {
+	if err := svc.Submit(ctx, acc, "again", nil, "", "web", "", "", ""); !errors.Is(err, feedback.ErrPendingReview) {
 		t.Fatalf("second submit err = %v, want ErrPendingReview", err)
 	}
 	if st, err := svc.State(ctx, acc); err != nil {
@@ -69,7 +69,7 @@ func TestFeedbackSubmitGateAndReplyLifecycle(t *testing.T) {
 	if m.Body != "please fix the board" { // trimmed
 		t.Fatalf("body = %q, want trimmed", m.Body)
 	}
-	if !m.HasAttachment || m.AttachmentName != "shot.png" || m.Channel != "ios" || m.SenderIP != "9.9.9.9" {
+	if !m.HasAttachment || m.AttachmentName != "shot.png" || m.Channel != "ios" || m.SenderIP != "9.9.9.9" || m.Version != "v1.2.0" || m.BrowserTZ != "+03:00" {
 		t.Fatalf("admin message = %+v", m)
 	}
 	if name, data, ok, err := svc.Attachment(ctx, id); err != nil || !ok || name != "shot.png" || string(data) != "PNGDATA" {
@@ -116,7 +116,7 @@ func TestFeedbackReplyHiddenAfterNewMessage(t *testing.T) {
 	acc := provisionAccount(t)
 
 	// msg1, replied → the player can send again and currently sees the reply.
-	if err := svc.Submit(ctx, acc, "first", nil, "", "web", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "first", nil, "", "web", "", "", ""); err != nil {
 		t.Fatalf("submit msg1: %v", err)
 	}
 	if err := svc.Reply(ctx, latestFeedbackID(t, svc, acc), "the answer"); err != nil {
@@ -130,7 +130,7 @@ func TestFeedbackReplyHiddenAfterNewMessage(t *testing.T) {
 
 	// Sending a new message immediately drops the previous reply (it now belongs to an
 	// older message), even though it is well within the one-week window.
-	if err := svc.Submit(ctx, acc, "second", nil, "", "web", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "second", nil, "", "web", "", "", ""); err != nil {
 		t.Fatalf("submit msg2: %v", err)
 	}
 	st, err := svc.State(ctx, acc)
@@ -154,7 +154,7 @@ func TestFeedbackSnapshotsLanguage(t *testing.T) {
 		t.Fatalf("set language: %v", err)
 	}
 	// A message snapshots the sender's interface language at submit time.
-	if err := svc.Submit(ctx, acc, "from telegram", nil, "", "telegram", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "from telegram", nil, "", "telegram", "", "", ""); err != nil {
 		t.Fatalf("submit: %v", err)
 	}
 	id := latestFeedbackID(t, svc, acc)
@@ -184,7 +184,7 @@ func TestFeedbackBanRole(t *testing.T) {
 	if err := accounts.GrantRole(ctx, acc, account.RoleFeedbackBanned); err != nil {
 		t.Fatalf("grant role: %v", err)
 	}
-	if err := svc.Submit(ctx, acc, "hi", nil, "", "web", ""); !errors.Is(err, feedback.ErrBanned) {
+	if err := svc.Submit(ctx, acc, "hi", nil, "", "web", "", "", ""); !errors.Is(err, feedback.ErrBanned) {
 		t.Fatalf("banned submit err = %v, want ErrBanned", err)
 	}
 	if st, err := svc.State(ctx, acc); err != nil {
@@ -196,7 +196,7 @@ func TestFeedbackBanRole(t *testing.T) {
 	if err := accounts.RevokeRole(ctx, acc, account.RoleFeedbackBanned); err != nil {
 		t.Fatalf("revoke role: %v", err)
 	}
-	if err := svc.Submit(ctx, acc, "hi again", nil, "", "web", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "hi again", nil, "", "web", "", "", ""); err != nil {
 		t.Fatalf("submit after unban: %v", err)
 	}
 }
@@ -219,7 +219,7 @@ func TestFeedbackValidation(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			acc := provisionAccount(t) // fresh account so the pending gate never fires first
-			if err := svc.Submit(ctx, acc, tt.body, tt.attachment, tt.attachmentName, "web", ""); !errors.Is(err, tt.want) {
+			if err := svc.Submit(ctx, acc, tt.body, tt.attachment, tt.attachmentName, "web", "", "", ""); !errors.Is(err, tt.want) {
 				t.Fatalf("submit err = %v, want %v", err, tt.want)
 			}
 		})
@@ -231,7 +231,7 @@ func TestFeedbackAdminLifecycle(t *testing.T) {
 	svc := newFeedbackService()
 	acc := provisionAccount(t)
 
-	if err := svc.Submit(ctx, acc, "first report", nil, "", "web", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "first report", nil, "", "web", "", "", ""); err != nil {
 		t.Fatalf("submit: %v", err)
 	}
 	id := latestFeedbackID(t, svc, acc)
@@ -276,7 +276,7 @@ func TestFeedbackDeleteAllByAccount(t *testing.T) {
 	svc := newFeedbackService()
 	acc := provisionAccount(t)
 
-	if err := svc.Submit(ctx, acc, "one", nil, "", "web", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "one", nil, "", "web", "", "", ""); err != nil {
 		t.Fatalf("submit: %v", err)
 	}
 	if err := svc.DeleteAllByAccount(ctx, acc); err != nil {
@@ -286,7 +286,7 @@ func TestFeedbackDeleteAllByAccount(t *testing.T) {
 	if has, err := svc.ReplyUnread(ctx, acc); err != nil || has {
 		t.Fatalf("reply unread after delete-all = %v (err %v)", has, err)
 	}
-	if err := svc.Submit(ctx, acc, "fresh", nil, "", "web", ""); err != nil {
+	if err := svc.Submit(ctx, acc, "fresh", nil, "", "web", "", "", ""); err != nil {
 		t.Fatalf("submit after delete-all: %v", err)
 	}
 }

backend/internal/inttest/helpers.go

@@ -120,7 +120,7 @@ func provisionAccount(t *testing.T) uuid.UUID {
 // provisionGuest creates a fresh ephemeral guest account and returns its id.
 func provisionGuest(t *testing.T) uuid.UUID {
 	t.Helper()
-	acc, err := account.NewStore(testDB).ProvisionGuest(context.Background())
+	acc, err := account.NewStore(testDB).ProvisionGuest(context.Background(), "")
 	if err != nil {
 		t.Fatalf("provision guest: %v", err)
 	}

backend/internal/inttest/link_change_test.go

@@ -0,0 +1,174 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/account"
+)
+
+// emailOf returns the external id of the account's email identity, or "" when it has none.
+func emailOf(t *testing.T, store *account.Store, id uuid.UUID) string {
+	t.Helper()
+	ids, err := store.Identities(context.Background(), id)
+	if err != nil {
+		t.Fatalf("identities %s: %v", id, err)
+	}
+	for _, i := range ids {
+		if i.Kind == account.KindEmail {
+			return i.ExternalID
+		}
+	}
+	return ""
+}
+
+// TestUnlinkProviderKeepsOthers detaches one provider from a multi-identity account and
+// refuses to remove the last remaining identity.
+func TestUnlinkProviderKeepsOthers(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision telegram: %v", err)
+	}
+	email := "unlink-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, email, true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+
+	// Removing a kind the account does not hold reports not-found.
+	if err := store.RemoveIdentity(ctx, acc.ID, account.KindVK); !errors.Is(err, account.ErrNotFound) {
+		t.Fatalf("remove absent vk = %v, want ErrNotFound", err)
+	}
+
+	// Detach Telegram: the email identity remains.
+	if err := store.RemoveIdentity(ctx, acc.ID, account.KindTelegram); err != nil {
+		t.Fatalf("remove telegram: %v", err)
+	}
+	ids, err := store.Identities(ctx, acc.ID)
+	if err != nil {
+		t.Fatalf("identities: %v", err)
+	}
+	if len(ids) != 1 || ids[0].Kind != account.KindEmail {
+		t.Fatalf("identities after unlink = %+v, want only email", ids)
+	}
+
+	// The email is now the last identity, so unlinking it is refused.
+	if err := store.RemoveIdentity(ctx, acc.ID, account.KindEmail); !errors.Is(err, account.ErrLastIdentity) {
+		t.Fatalf("remove last email = %v, want ErrLastIdentity", err)
+	}
+}
+
+// TestChangeEmailReplaces switches an account's confirmed email to a free address,
+// freeing the old one.
+func TestChangeEmailReplaces(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	oldAddr := "old-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, oldAddr, true); err != nil {
+		t.Fatalf("attach old email: %v", err)
+	}
+	newAddr := "new-" + uuid.NewString() + "@example.com"
+
+	if err := svc.RequestChangeCode(ctx, acc.ID, newAddr); err != nil {
+		t.Fatalf("request change: %v", err)
+	}
+	code := sixDigit.FindString(mailer.lastBody)
+	if _, err := svc.ConfirmChange(ctx, acc.ID, newAddr, code); err != nil {
+		t.Fatalf("confirm change: %v", err)
+	}
+	if got := emailOf(t, store, acc.ID); got != newAddr {
+		t.Fatalf("email after change = %q, want %q", got, newAddr)
+	}
+	if !identityConfirmed(t, account.KindEmail, newAddr) {
+		t.Error("the new email identity must be confirmed")
+	}
+	// The old address is freed: another account can now claim it.
+	other, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision other: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, other.ID, account.KindEmail, oldAddr, true); err != nil {
+		t.Fatalf("old address should be free after change, got: %v", err)
+	}
+}
+
+// TestChangeEmailRefusesTaken refuses (without merging) a new address already confirmed by
+// another account, leaving the caller's email untouched.
+func TestChangeEmailRefusesTaken(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision caller: %v", err)
+	}
+	mine := "mine-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, mine, true); err != nil {
+		t.Fatalf("attach caller email: %v", err)
+	}
+	other, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision other: %v", err)
+	}
+	taken := "taken-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, other.ID, account.KindEmail, taken, true); err != nil {
+		t.Fatalf("attach other email: %v", err)
+	}
+
+	if err := svc.RequestChangeCode(ctx, acc.ID, taken); err != nil {
+		t.Fatalf("request change: %v", err)
+	}
+	code := sixDigit.FindString(mailer.lastBody)
+	if _, err := svc.ConfirmChange(ctx, acc.ID, taken, code); !errors.Is(err, account.ErrEmailTaken) {
+		t.Fatalf("confirm change to taken = %v, want ErrEmailTaken", err)
+	}
+	if got := emailOf(t, store, acc.ID); got != mine {
+		t.Errorf("caller email after refused change = %q, want unchanged %q", got, mine)
+	}
+}
+
+// TestChangeEmailViaDeeplink switches the email through the one-tap confirm token.
+func TestChangeEmailViaDeeplink(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, "old-"+uuid.NewString()+"@example.com", true); err != nil {
+		t.Fatalf("attach old email: %v", err)
+	}
+	newAddr := "dl-" + uuid.NewString() + "@example.com"
+	if err := svc.RequestChangeCode(ctx, acc.ID, newAddr); err != nil {
+		t.Fatalf("request change: %v", err)
+	}
+	res, err := svc.ConfirmByToken(ctx, tokenFromMail(t, mailer.lastBody))
+	if err != nil {
+		t.Fatalf("confirm by token: %v", err)
+	}
+	if res.IsLogin() || res.NeedsMerge || res.Account != acc.ID {
+		t.Fatalf("deeplink change result = %+v, want a plain change for %s", res, acc.ID)
+	}
+	if got := emailOf(t, store, acc.ID); got != newAddr {
+		t.Fatalf("email after deeplink change = %q, want %q", got, newAddr)
+	}
+}

backend/internal/inttest/merge_test.go

@@ -119,7 +119,7 @@ func seatGame(t *testing.T, seats []uuid.UUID, timeout time.Duration) uuid.UUID
 
 func newLinkService(mailer account.Mailer) *link.Service {
 	store := account.NewStore(testDB)
-	emails := account.NewEmailService(store, mailer)
+	emails := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 	sessions := session.NewService(session.NewStore(testDB), session.NewCache())
 	return link.NewService(emails, store, accountmerge.NewMerger(testDB), sessions)
 }
@@ -251,6 +251,44 @@ func TestAccountMergeFinishedSharedGameKept(t *testing.T) {
 	}
 }
 
+// TestAccountMergeDedupesEmail keeps the primary's email when both accounts have one and
+// journals the secondary's to the dossier (reason=merge), so the survivor never ends up
+// with two email identities.
+func TestAccountMergeDedupesEmail(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	merger := accountmerge.NewMerger(testDB)
+
+	primary := provisionAccount(t)
+	secondary := provisionAccount(t)
+	primaryEmail := "keep-" + uuid.NewString() + "@example.com"
+	secondaryEmail := "absorb-" + uuid.NewString() + "@example.com"
+	bindEmailIdentity(t, primary, primaryEmail)
+	bindEmailIdentity(t, secondary, secondaryEmail)
+
+	if err := merger.Merge(ctx, primary, secondary); err != nil {
+		t.Fatalf("merge: %v", err)
+	}
+
+	// The primary keeps its own email; the secondary's is gone from the live identities.
+	if owner, ok, _ := store.AccountIDByIdentity(ctx, account.KindEmail, primaryEmail); !ok || owner != primary {
+		t.Errorf("primary email owner = %s ok=%v, want primary %s", owner, ok, primary)
+	}
+	if _, ok, _ := store.AccountIDByIdentity(ctx, account.KindEmail, secondaryEmail); ok {
+		t.Error("the secondary's email must be removed (no duplicate email on the survivor)")
+	}
+	// The absorbed email stays in the legal dossier, tagged reason=merge.
+	var reason string
+	if err := testDB.QueryRowContext(ctx,
+		`SELECT reason FROM backend.retained_identities WHERE account_id=$1 AND kind='email' AND external_id=$2`,
+		secondary, secondaryEmail).Scan(&reason); err != nil {
+		t.Fatalf("retained email row: %v", err)
+	}
+	if reason != "merge" {
+		t.Errorf("retained reason = %q, want merge", reason)
+	}
+}
+
 // TestAccountLinkFreeEmail binds a free email and promotes a guest to durable.
 func TestAccountLinkFreeEmail(t *testing.T) {
 	ctx := context.Background()
@@ -355,3 +393,64 @@ func TestAccountLinkGuestInversion(t *testing.T) {
 		t.Errorf("email owner = %s, want durable", owner)
 	}
 }
+
+// TestAccountLinkFreeVK binds a free VK identity (gateway-validated, no code) and
+// promotes a guest to durable — the ConfirmVK counterpart of the free-email case.
+func TestAccountLinkFreeVK(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	links := newLinkService(&capturingMailer{})
+
+	guest := provisionGuest(t)
+	vkID := "vk-" + uuid.NewString()
+	res, err := links.ConfirmVK(ctx, guest, vkID)
+	if err != nil {
+		t.Fatalf("confirm vk: %v", err)
+	}
+	if !res.Linked || res.MergeRequired {
+		t.Fatalf("confirm = %+v, want linked", res)
+	}
+	if acc, _ := store.GetByID(ctx, guest); acc.IsGuest {
+		t.Error("guest flag should clear once VK is linked")
+	}
+	if owner, ok, _ := store.AccountIDByIdentity(ctx, account.KindVK, vkID); !ok || owner != guest {
+		t.Errorf("vk owner = %s, want the promoted guest %s", owner, guest)
+	}
+}
+
+// TestAccountLinkVKMergeIntoCaller merges the account owning a VK identity into the
+// current durable account: ConfirmVK previews the merge, MergeVK folds it, the caller
+// stays primary and keeps its session, and the VK identity repoints to the caller.
+func TestAccountLinkVKMergeIntoCaller(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	links := newLinkService(&capturingMailer{})
+
+	caller := provisionAccount(t)
+	other := provisionAccount(t)
+	vkID := "vk-" + uuid.NewString()
+	if err := store.AttachIdentity(ctx, other, account.KindVK, vkID, true); err != nil {
+		t.Fatalf("seed vk on other: %v", err)
+	}
+
+	confirm, err := links.ConfirmVK(ctx, caller, vkID)
+	if err != nil {
+		t.Fatalf("confirm vk: %v", err)
+	}
+	if !confirm.MergeRequired || confirm.SecondaryID != other {
+		t.Fatalf("confirm = %+v, want merge_required to other %s", confirm, other)
+	}
+	merge, err := links.MergeVK(ctx, caller, vkID)
+	if err != nil {
+		t.Fatalf("merge vk: %v", err)
+	}
+	if merge.PrimaryID != caller || merge.SwitchedToken != "" {
+		t.Fatalf("merge = %+v, want primary caller and no session switch", merge)
+	}
+	if mergedInto(t, other) != caller {
+		t.Error("other should be tombstoned into caller")
+	}
+	if owner, _, _ := store.AccountIDByIdentity(ctx, account.KindVK, vkID); owner != caller {
+		t.Errorf("vk owner = %s, want caller after merge", owner)
+	}
+}

backend/internal/inttest/promo_variant_test.go

@@ -0,0 +1,80 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap/zaptest"
+
+	"scrabble/backend/internal/account"
+	"scrabble/backend/internal/server"
+	"scrabble/backend/internal/session"
+)
+
+// TestTelegramAuthSeedsPromoVariantForNewUserOnly drives the sessions/telegram endpoint
+// to confirm a promo deep-link start-param seeds a brand-new account's variant
+// preferences (English Scrabble alongside the default Erudit), that a new account with no
+// such payload keeps the Erudit-only default, and that an existing account is never
+// re-seeded on a later login (the new-user-only contract).
+func TestTelegramAuthSeedsPromoVariantForNewUserOnly(t *testing.T) {
+	srv := server.New(":0", server.Deps{
+		Logger:   zaptest.NewLogger(t),
+		DB:       testDB,
+		Accounts: account.NewStore(testDB),
+		Sessions: session.NewService(session.NewStore(testDB), session.NewCache()),
+		Notifier: &captureNotifier{},
+	})
+	h := srv.Handler()
+
+	post := func(ext, startParam string) {
+		body := `{"external_id":"` + ext + `","language_code":"en","first_name":"Promo"`
+		if startParam != "" {
+			body += `,"start_param":"` + startParam + `"`
+		}
+		body += `}`
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodPost, "/api/v1/internal/sessions/telegram", strings.NewReader(body))
+		req.Header.Set("Content-Type", "application/json")
+		h.ServeHTTP(rec, req)
+		if rec.Code != http.StatusOK {
+			t.Fatalf("telegram auth = %d: %s", rec.Code, rec.Body.String())
+		}
+	}
+	store := account.NewStore(testDB)
+	reload := func(ext string) []string {
+		acc, err := store.AccountByIdentity(context.Background(), account.KindTelegram, ext)
+		if err != nil {
+			t.Fatalf("lookup %s: %v", ext, err)
+		}
+		return acc.VariantPreferences
+	}
+
+	// A brand-new account reached through a promo deep-link is seeded with English
+	// Scrabble alongside the default Erudit.
+	promoExt := "tg-" + uuid.NewString()
+	post(promoExt, "verudit_ru-scrabble_en")
+	if got, want := reload(promoExt), []string{"erudit_ru", "scrabble_en"}; !slices.Equal(got, want) {
+		t.Errorf("promo new account variants = %v, want %v", got, want)
+	}
+
+	// A brand-new account with no promo payload keeps the Erudit-only default.
+	plainExt := "tg-" + uuid.NewString()
+	post(plainExt, "")
+	if got, want := reload(plainExt), []string{"erudit_ru"}; !slices.Equal(got, want) {
+		t.Errorf("plain new account variants = %v, want %v", got, want)
+	}
+
+	// A later login of the promo account, even via a different payload, must not re-seed:
+	// the seed is first-contact only.
+	post(promoExt, "vscrabble_ru")
+	if got, want := reload(promoExt), []string{"erudit_ru", "scrabble_en"}; !slices.Equal(got, want) {
+		t.Errorf("existing account re-seeded = %v, want unchanged %v", got, want)
+	}
+}

backend/internal/inttest/retention_test.go

@@ -0,0 +1,192 @@
+//go:build integration
+
+package inttest
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/account"
+	"scrabble/backend/internal/accountdelete"
+)
+
+// lastLoginIP reads an account's stamped last-login IP ("" when unset).
+func lastLoginIP(t *testing.T, accountID uuid.UUID) string {
+	t.Helper()
+	var ip sql.NullString
+	err := testDB.QueryRowContext(context.Background(),
+		"SELECT last_login_ip FROM accounts WHERE account_id = $1", accountID).Scan(&ip)
+	if err != nil {
+		t.Fatalf("read last_login_ip %s: %v", accountID, err)
+	}
+	return ip.String
+}
+
+// retainedRow is one row of the retention journal, read directly for assertions.
+type retainedRow struct {
+	kind, externalID, reason string
+}
+
+// retainedRows reads the retention journal for an account, oldest detach first.
+func retainedRows(t *testing.T, accountID uuid.UUID) []retainedRow {
+	t.Helper()
+	rows, err := testDB.QueryContext(context.Background(),
+		"SELECT kind, external_id, reason FROM retained_identities WHERE account_id = $1 ORDER BY detached_at",
+		accountID)
+	if err != nil {
+		t.Fatalf("query retained_identities %s: %v", accountID, err)
+	}
+	defer rows.Close()
+	var out []retainedRow
+	for rows.Next() {
+		var r retainedRow
+		if err := rows.Scan(&r.kind, &r.externalID, &r.reason); err != nil {
+			t.Fatalf("scan retained row: %v", err)
+		}
+		out = append(out, r)
+	}
+	return out
+}
+
+// TestUnlinkJournalsRetainedIdentity: detaching a provider records it in the retention
+// journal (reason=unlink) before the live identity is removed.
+func TestUnlinkJournalsRetainedIdentity(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+
+	tgExt := "tg-" + uuid.NewString()
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, tgExt)
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	email := "keep-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, email, true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+
+	if err := store.RemoveIdentity(ctx, acc.ID, account.KindTelegram); err != nil {
+		t.Fatalf("unlink telegram: %v", err)
+	}
+	got := retainedRows(t, acc.ID)
+	if len(got) != 1 || got[0].kind != account.KindTelegram || got[0].externalID != tgExt || got[0].reason != "unlink" {
+		t.Fatalf("retained rows = %+v, want one unlink telegram %q", got, tgExt)
+	}
+}
+
+// TestChangeEmailJournalsOldAddress: an email change records the outgoing address in the
+// retention journal (reason=change).
+func TestChangeEmailJournalsOldAddress(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
+
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	oldAddr := "old-" + uuid.NewString() + "@example.com"
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, oldAddr, true); err != nil {
+		t.Fatalf("attach old email: %v", err)
+	}
+	newAddr := "new-" + uuid.NewString() + "@example.com"
+	if err := svc.RequestChangeCode(ctx, acc.ID, newAddr); err != nil {
+		t.Fatalf("request change: %v", err)
+	}
+	if _, err := svc.ConfirmChange(ctx, acc.ID, newAddr, sixDigit.FindString(mailer.lastBody)); err != nil {
+		t.Fatalf("confirm change: %v", err)
+	}
+	got := retainedRows(t, acc.ID)
+	if len(got) != 1 || got[0].kind != account.KindEmail || got[0].externalID != oldAddr || got[0].reason != "change" {
+		t.Fatalf("retained rows = %+v, want one change email %q", got, oldAddr)
+	}
+}
+
+// TestStampLastLoginThrottles: the first cold-load stamp writes the IP; a second within
+// the hour is a no-op (throttled), so it costs at most one write per account per hour.
+func TestStampLastLoginThrottles(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, "tg-"+uuid.NewString())
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	if err := store.StampLastLogin(ctx, acc.ID, "1.2.3.4"); err != nil {
+		t.Fatalf("first stamp: %v", err)
+	}
+	if got := lastLoginIP(t, acc.ID); got != "1.2.3.4" {
+		t.Fatalf("first stamp ip = %q, want 1.2.3.4", got)
+	}
+	if err := store.StampLastLogin(ctx, acc.ID, "9.9.9.9"); err != nil {
+		t.Fatalf("second stamp: %v", err)
+	}
+	if got := lastLoginIP(t, acc.ID); got != "1.2.3.4" {
+		t.Fatalf("throttled ip = %q, want unchanged 1.2.3.4", got)
+	}
+}
+
+// TestReapExpiredRetention: the reaper keeps journal rows newer than the cutoff and purges
+// older ones, and drops a long-deleted account's feedback thread + dossier PII.
+func TestReapExpiredRetention(t *testing.T) {
+	ctx := context.Background()
+	store := account.NewStore(testDB)
+	deleter := accountdelete.NewDeleter(testDB)
+
+	// An unlinked provider leaves a journal row detached "now".
+	tgExt := "tg-" + uuid.NewString()
+	acc, err := store.ProvisionByIdentity(ctx, account.KindTelegram, tgExt)
+	if err != nil {
+		t.Fatalf("provision: %v", err)
+	}
+	if err := store.AttachIdentity(ctx, acc.ID, account.KindEmail, "keep-"+uuid.NewString()+"@example.com", true); err != nil {
+		t.Fatalf("attach email: %v", err)
+	}
+	if err := store.RemoveIdentity(ctx, acc.ID, account.KindTelegram); err != nil {
+		t.Fatalf("unlink: %v", err)
+	}
+	// A cutoff before the detach keeps the row.
+	if _, _, err := store.ReapExpiredRetention(ctx, time.Now().Add(-time.Hour)); err != nil {
+		t.Fatalf("reap (early cutoff): %v", err)
+	}
+	if got := retainedRows(t, acc.ID); len(got) != 1 {
+		t.Fatalf("journal after early-cutoff reap = %+v, want kept", got)
+	}
+	// A cutoff after the detach purges it.
+	if _, _, err := store.ReapExpiredRetention(ctx, time.Now().Add(time.Hour)); err != nil {
+		t.Fatalf("reap (late cutoff): %v", err)
+	}
+	if got := retainedRows(t, acc.ID); len(got) != 0 {
+		t.Fatalf("journal after late-cutoff reap = %+v, want purged", got)
+	}
+
+	// A deleted account past the cutoff loses its feedback thread and dossier PII.
+	del, _, err := store.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "ru", "", "Иван", "")
+	if err != nil {
+		t.Fatalf("provision deletee: %v", err)
+	}
+	if _, err := testDB.ExecContext(ctx,
+		"INSERT INTO feedback_messages (message_id, account_id, body, channel) VALUES ($1, $2, 'hi', 'web')",
+		uuid.New(), del.ID); err != nil {
+		t.Fatalf("insert feedback: %v", err)
+	}
+	if err := deleter.AnonymizeAndTombstone(ctx, del.ID); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	if _, fb, err := store.ReapExpiredRetention(ctx, time.Now().Add(time.Hour)); err != nil || fb == 0 {
+		t.Fatalf("reap deleted = (fb %d, err %v), want fb>=1", fb, err)
+	}
+	if name, _ := deletedFields(t, del.ID); name != "" {
+		t.Errorf("deleted_display_name after reap = %q, want cleared", name)
+	}
+	var fbCount int
+	if err := testDB.QueryRowContext(ctx, "SELECT count(*) FROM feedback_messages WHERE account_id = $1", del.ID).Scan(&fbCount); err != nil {
+		t.Fatalf("count feedback: %v", err)
+	}
+	if fbCount != 0 {
+		t.Errorf("feedback rows after reap = %d, want 0", fbCount)
+	}
+}

backend/internal/inttest/suspension_gate_test.go

@@ -38,7 +38,7 @@ func TestSuspensionGate(t *testing.T) {
 		Accounts: accounts,
 	})
 
-	acc, _, err := accounts.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "ru", "", "Blocked")
+	acc, _, err := accounts.ProvisionTelegram(ctx, "tg-"+uuid.NewString(), "ru", "", "Blocked", "")
 	if err != nil {
 		t.Fatalf("provision: %v", err)
 	}

backend/internal/inttest/userlist_test.go

@@ -18,7 +18,7 @@ func TestUserListFilter(t *testing.T) {
 	st := account.NewStore(testDB)
 	uniq := uuid.NewString()
 
-	human, _, err := st.ProvisionTelegram(ctx, "tg-"+uniq, "en", "", "Zzqxhuman")
+	human, _, err := st.ProvisionTelegram(ctx, "tg-"+uniq, "en", "", "Zzqxhuman", "")
 	if err != nil {
 		t.Fatalf("provision human: %v", err)
 	}
@@ -26,7 +26,7 @@ func TestUserListFilter(t *testing.T) {
 	if err != nil {
 		t.Fatalf("provision robot: %v", err)
 	}
-	guest, err := st.ProvisionGuest(ctx)
+	guest, err := st.ProvisionGuest(ctx, "")
 	if err != nil {
 		t.Fatalf("provision guest: %v", err)
 	}

backend/internal/link/service.go

@@ -133,6 +133,53 @@ func (s *Service) attachTelegram(ctx context.Context, callerID uuid.UUID, extern
 	return s.accounts.ClearGuest(ctx, callerID)
 }
 
+// ConfirmVK attaches a gateway-validated VK identity to the caller (Linked) or
+// reports that it belongs to another account (MergeRequired). The gateway has already
+// completed the VK ID code exchange, so externalID is the trusted vk user id.
+func (s *Service) ConfirmVK(ctx context.Context, callerID uuid.UUID, externalID string) (ConfirmResult, error) {
+	owner, ok, err := s.accounts.AccountIDByIdentity(ctx, account.KindVK, externalID)
+	if err != nil {
+		return ConfirmResult{}, err
+	}
+	if !ok {
+		if err := s.attachVK(ctx, callerID, externalID); err != nil {
+			return ConfirmResult{}, err
+		}
+		return ConfirmResult{Linked: true}, nil
+	}
+	if owner == callerID {
+		return ConfirmResult{Linked: true}, nil
+	}
+	return ConfirmResult{MergeRequired: true, SecondaryID: owner}, nil
+}
+
+// MergeVK merges the account owning a gateway-validated VK identity into the caller's
+// (subject to the guest-primary rule).
+func (s *Service) MergeVK(ctx context.Context, callerID uuid.UUID, externalID string) (MergeResult, error) {
+	owner, ok, err := s.accounts.AccountIDByIdentity(ctx, account.KindVK, externalID)
+	if err != nil {
+		return MergeResult{}, err
+	}
+	if !ok {
+		if err := s.attachVK(ctx, callerID, externalID); err != nil {
+			return MergeResult{}, err
+		}
+		return MergeResult{PrimaryID: callerID}, nil
+	}
+	if owner == callerID {
+		return MergeResult{PrimaryID: callerID}, nil
+	}
+	return s.merge(ctx, callerID, owner)
+}
+
+// attachVK links the identity to the caller and promotes a guest.
+func (s *Service) attachVK(ctx context.Context, callerID uuid.UUID, externalID string) error {
+	if err := s.accounts.AttachIdentity(ctx, callerID, account.KindVK, externalID, true); err != nil {
+		return err
+	}
+	return s.accounts.ClearGuest(ctx, callerID)
+}
+
 // merge decides the primary (the caller, unless it is a guest and the other is
 // durable), runs the data merge, retires the secondary's sessions and mints a new
 // session when the active account switches.

backend/internal/notify/events.go

@@ -155,6 +155,13 @@ func Notification(userID uuid.UUID, kind string) Intent {
 	return Intent{UserID: userID, Kind: KindNotification, Payload: b.FinishedBytes(), EventID: eventID()}
 }
 
+// ProfileChanged is a payload-free "re-fetch your profile" signal to userID, emitted
+// when the viewer's own account changed out of band — an email confirmed through the
+// one-tap deeplink opened in another browser.
+func ProfileChanged(userID uuid.UUID) Intent {
+	return Notification(userID, NotifyProfile)
+}
+
 // NotificationAccount builds a lobby notification of one of the friend_* kinds carrying the
 // account it concerns (the requester, the new friend or the decliner), so the client updates its
 // requests/friends lists and the in-game "add friend" state without a refetch.

backend/internal/notify/notify.go

@@ -69,6 +69,10 @@ const (
 	// it re-fetches profile.get to show or hide the banner. It carries no payload (the
 	// banner set rides the profile response). In-app only.
 	NotifyBanner = "banner"
+	// NotifyProfile tells the client that the viewer's own profile changed out of band
+	// (e.g. an email was confirmed via the one-tap deeplink opened in another browser),
+	// so it re-fetches profile.get. It carries no payload. In-app only.
+	NotifyProfile = "profile"
 	// NotifyUserBlocked confirms to the blocker that a per-user block took effect,
 	// carrying the blocked account, so every one of the blocker's sessions updates the
 	// in-game block/add-friend controls and the struck name in place. It is delivered

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

@@ -32,4 +32,8 @@ type Accounts struct {
 	MergedAt               *time.Time
 	FlaggedHighRateAt      *time.Time
 	VariantPreferences     pq.StringArray
+	LastLoginAt            *time.Time
+	LastLoginIP            *string
+	DeletedAt              *time.Time
+	DeletedDisplayName     *string
 }

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

@@ -21,4 +21,6 @@ type EmailConfirmations struct {
 	Attempts       int16
 	ConsumedAt     *time.Time
 	CreatedAt      time.Time
+	Purpose        string
+	LinkTokenHash  *string
 }

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

@@ -0,0 +1,24 @@
+//
+// 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 RetainedIdentities struct {
+	RetainedID uuid.UUID `sql:"primary_key"`
+	AccountID  uuid.UUID
+	Kind       string
+	ExternalID string
+	Confirmed  bool
+	LinkedAt   time.Time
+	DetachedAt time.Time
+	Reason     string
+}

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

@@ -35,6 +35,10 @@ type accountsTable struct {
 	MergedAt               postgres.ColumnTimestampz
 	FlaggedHighRateAt      postgres.ColumnTimestampz
 	VariantPreferences     postgres.ColumnStringArray
+	LastLoginAt            postgres.ColumnTimestampz
+	LastLoginIP            postgres.ColumnString
+	DeletedAt              postgres.ColumnTimestampz
+	DeletedDisplayName     postgres.ColumnString
 
 	AllColumns     postgres.ColumnList
 	MutableColumns postgres.ColumnList
@@ -94,8 +98,12 @@ func newAccountsTableImpl(schemaName, tableName, alias string) accountsTable {
 		MergedAtColumn               = postgres.TimestampzColumn("merged_at")
 		FlaggedHighRateAtColumn      = postgres.TimestampzColumn("flagged_high_rate_at")
 		VariantPreferencesColumn     = postgres.StringArrayColumn("variant_preferences")
-		allColumns                   = postgres.ColumnList{AccountIDColumn, DisplayNameColumn, PreferredLanguageColumn, TimeZoneColumn, BlockChatColumn, BlockFriendRequestsColumn, CreatedAtColumn, UpdatedAtColumn, AwayStartColumn, AwayEndColumn, HintBalanceColumn, IsGuestColumn, NotificationsInAppOnlyColumn, PaidAccountColumn, MergedIntoColumn, MergedAtColumn, FlaggedHighRateAtColumn, VariantPreferencesColumn}
+		LastLoginAtColumn            = postgres.TimestampzColumn("last_login_at")
-		mutableColumns               = postgres.ColumnList{DisplayNameColumn, PreferredLanguageColumn, TimeZoneColumn, BlockChatColumn, BlockFriendRequestsColumn, CreatedAtColumn, UpdatedAtColumn, AwayStartColumn, AwayEndColumn, HintBalanceColumn, IsGuestColumn, NotificationsInAppOnlyColumn, PaidAccountColumn, MergedIntoColumn, MergedAtColumn, FlaggedHighRateAtColumn, VariantPreferencesColumn}
+		LastLoginIPColumn            = postgres.StringColumn("last_login_ip")
+		DeletedAtColumn              = postgres.TimestampzColumn("deleted_at")
+		DeletedDisplayNameColumn     = postgres.StringColumn("deleted_display_name")
+		allColumns                   = postgres.ColumnList{AccountIDColumn, DisplayNameColumn, PreferredLanguageColumn, TimeZoneColumn, BlockChatColumn, BlockFriendRequestsColumn, CreatedAtColumn, UpdatedAtColumn, AwayStartColumn, AwayEndColumn, HintBalanceColumn, IsGuestColumn, NotificationsInAppOnlyColumn, PaidAccountColumn, MergedIntoColumn, MergedAtColumn, FlaggedHighRateAtColumn, VariantPreferencesColumn, LastLoginAtColumn, LastLoginIPColumn, DeletedAtColumn, DeletedDisplayNameColumn}
+		mutableColumns               = postgres.ColumnList{DisplayNameColumn, PreferredLanguageColumn, TimeZoneColumn, BlockChatColumn, BlockFriendRequestsColumn, CreatedAtColumn, UpdatedAtColumn, AwayStartColumn, AwayEndColumn, HintBalanceColumn, IsGuestColumn, NotificationsInAppOnlyColumn, PaidAccountColumn, MergedIntoColumn, MergedAtColumn, FlaggedHighRateAtColumn, VariantPreferencesColumn, LastLoginAtColumn, LastLoginIPColumn, DeletedAtColumn, DeletedDisplayNameColumn}
 		defaultColumns               = postgres.ColumnList{DisplayNameColumn, PreferredLanguageColumn, TimeZoneColumn, BlockChatColumn, BlockFriendRequestsColumn, CreatedAtColumn, UpdatedAtColumn, AwayStartColumn, AwayEndColumn, HintBalanceColumn, IsGuestColumn, NotificationsInAppOnlyColumn, PaidAccountColumn, VariantPreferencesColumn}
 	)
 
@@ -121,6 +129,10 @@ func newAccountsTableImpl(schemaName, tableName, alias string) accountsTable {
 		MergedAt:               MergedAtColumn,
 		FlaggedHighRateAt:      FlaggedHighRateAtColumn,
 		VariantPreferences:     VariantPreferencesColumn,
+		LastLoginAt:            LastLoginAtColumn,
+		LastLoginIP:            LastLoginIPColumn,
+		DeletedAt:              DeletedAtColumn,
+		DeletedDisplayName:     DeletedDisplayNameColumn,
 
 		AllColumns:     allColumns,
 		MutableColumns: mutableColumns,

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

@@ -25,6 +25,8 @@ type emailConfirmationsTable struct {
 	Attempts       postgres.ColumnInteger
 	ConsumedAt     postgres.ColumnTimestampz
 	CreatedAt      postgres.ColumnTimestampz
+	Purpose        postgres.ColumnString
+	LinkTokenHash  postgres.ColumnString
 
 	AllColumns     postgres.ColumnList
 	MutableColumns postgres.ColumnList
@@ -74,9 +76,11 @@ func newEmailConfirmationsTableImpl(schemaName, tableName, alias string) emailCo
 		AttemptsColumn       = postgres.IntegerColumn("attempts")
 		ConsumedAtColumn     = postgres.TimestampzColumn("consumed_at")
 		CreatedAtColumn      = postgres.TimestampzColumn("created_at")
-		allColumns           = postgres.ColumnList{ConfirmationIDColumn, AccountIDColumn, EmailColumn, CodeHashColumn, ExpiresAtColumn, AttemptsColumn, ConsumedAtColumn, CreatedAtColumn}
+		PurposeColumn        = postgres.StringColumn("purpose")
-		mutableColumns       = postgres.ColumnList{AccountIDColumn, EmailColumn, CodeHashColumn, ExpiresAtColumn, AttemptsColumn, ConsumedAtColumn, CreatedAtColumn}
+		LinkTokenHashColumn  = postgres.StringColumn("link_token_hash")
-		defaultColumns       = postgres.ColumnList{AttemptsColumn, CreatedAtColumn}
+		allColumns           = postgres.ColumnList{ConfirmationIDColumn, AccountIDColumn, EmailColumn, CodeHashColumn, ExpiresAtColumn, AttemptsColumn, ConsumedAtColumn, CreatedAtColumn, PurposeColumn, LinkTokenHashColumn}
+		mutableColumns       = postgres.ColumnList{AccountIDColumn, EmailColumn, CodeHashColumn, ExpiresAtColumn, AttemptsColumn, ConsumedAtColumn, CreatedAtColumn, PurposeColumn, LinkTokenHashColumn}
+		defaultColumns       = postgres.ColumnList{AttemptsColumn, CreatedAtColumn, PurposeColumn}
 	)
 
 	return emailConfirmationsTable{
@@ -91,6 +95,8 @@ func newEmailConfirmationsTableImpl(schemaName, tableName, alias string) emailCo
 		Attempts:       AttemptsColumn,
 		ConsumedAt:     ConsumedAtColumn,
 		CreatedAt:      CreatedAtColumn,
+		Purpose:        PurposeColumn,
+		LinkTokenHash:  LinkTokenHashColumn,
 
 		AllColumns:     allColumns,
 		MutableColumns: mutableColumns,

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

@@ -0,0 +1,99 @@
+//
+// 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 RetainedIdentities = newRetainedIdentitiesTable("backend", "retained_identities", "")
+
+type retainedIdentitiesTable struct {
+	postgres.Table
+
+	// Columns
+	RetainedID postgres.ColumnString
+	AccountID  postgres.ColumnString
+	Kind       postgres.ColumnString
+	ExternalID postgres.ColumnString
+	Confirmed  postgres.ColumnBool
+	LinkedAt   postgres.ColumnTimestampz
+	DetachedAt postgres.ColumnTimestampz
+	Reason     postgres.ColumnString
+
+	AllColumns     postgres.ColumnList
+	MutableColumns postgres.ColumnList
+	DefaultColumns postgres.ColumnList
+}
+
+type RetainedIdentitiesTable struct {
+	retainedIdentitiesTable
+
+	EXCLUDED retainedIdentitiesTable
+}
+
+// AS creates new RetainedIdentitiesTable with assigned alias
+func (a RetainedIdentitiesTable) AS(alias string) *RetainedIdentitiesTable {
+	return newRetainedIdentitiesTable(a.SchemaName(), a.TableName(), alias)
+}
+
+// Schema creates new RetainedIdentitiesTable with assigned schema name
+func (a RetainedIdentitiesTable) FromSchema(schemaName string) *RetainedIdentitiesTable {
+	return newRetainedIdentitiesTable(schemaName, a.TableName(), a.Alias())
+}
+
+// WithPrefix creates new RetainedIdentitiesTable with assigned table prefix
+func (a RetainedIdentitiesTable) WithPrefix(prefix string) *RetainedIdentitiesTable {
+	return newRetainedIdentitiesTable(a.SchemaName(), prefix+a.TableName(), a.TableName())
+}
+
+// WithSuffix creates new RetainedIdentitiesTable with assigned table suffix
+func (a RetainedIdentitiesTable) WithSuffix(suffix string) *RetainedIdentitiesTable {
+	return newRetainedIdentitiesTable(a.SchemaName(), a.TableName()+suffix, a.TableName())
+}
+
+func newRetainedIdentitiesTable(schemaName, tableName, alias string) *RetainedIdentitiesTable {
+	return &RetainedIdentitiesTable{
+		retainedIdentitiesTable: newRetainedIdentitiesTableImpl(schemaName, tableName, alias),
+		EXCLUDED:                newRetainedIdentitiesTableImpl("", "excluded", ""),
+	}
+}
+
+func newRetainedIdentitiesTableImpl(schemaName, tableName, alias string) retainedIdentitiesTable {
+	var (
+		RetainedIDColumn = postgres.StringColumn("retained_id")
+		AccountIDColumn  = postgres.StringColumn("account_id")
+		KindColumn       = postgres.StringColumn("kind")
+		ExternalIDColumn = postgres.StringColumn("external_id")
+		ConfirmedColumn  = postgres.BoolColumn("confirmed")
+		LinkedAtColumn   = postgres.TimestampzColumn("linked_at")
+		DetachedAtColumn = postgres.TimestampzColumn("detached_at")
+		ReasonColumn     = postgres.StringColumn("reason")
+		allColumns       = postgres.ColumnList{RetainedIDColumn, AccountIDColumn, KindColumn, ExternalIDColumn, ConfirmedColumn, LinkedAtColumn, DetachedAtColumn, ReasonColumn}
+		mutableColumns   = postgres.ColumnList{AccountIDColumn, KindColumn, ExternalIDColumn, ConfirmedColumn, LinkedAtColumn, DetachedAtColumn, ReasonColumn}
+		defaultColumns   = postgres.ColumnList{ConfirmedColumn, DetachedAtColumn}
+	)
+
+	return retainedIdentitiesTable{
+		Table: postgres.NewTable(schemaName, tableName, alias, allColumns...),
+
+		//Columns
+		RetainedID: RetainedIDColumn,
+		AccountID:  AccountIDColumn,
+		Kind:       KindColumn,
+		ExternalID: ExternalIDColumn,
+		Confirmed:  ConfirmedColumn,
+		LinkedAt:   LinkedAtColumn,
+		DetachedAt: DetachedAtColumn,
+		Reason:     ReasonColumn,
+
+		AllColumns:     allColumns,
+		MutableColumns: mutableColumns,
+		DefaultColumns: defaultColumns,
+	}
+}

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

@@ -34,6 +34,7 @@ func UseSchema(schema string) {
 	GameSetupDraws = GameSetupDraws.FromSchema(schema)
 	Games = Games.FromSchema(schema)
 	Identities = Identities.FromSchema(schema)
+	RetainedIdentities = RetainedIdentities.FromSchema(schema)
 	Sessions = Sessions.FromSchema(schema)
 	SuspensionReasons = SuspensionReasons.FromSchema(schema)
 }

backend/internal/postgres/migrations/00002_default_ad_tips.sql

@@ -0,0 +1,64 @@
+-- Replace the default (house) ad campaign's single seed tip with the curated,
+-- language-agnostic Scrabble tip set (one bilingual row per tip; the client picks the
+-- column for the viewer's language). Data-only — the ad_messages schema is unchanged, so
+-- a backend image rollback stays DB-safe. The default campaign is the fixed house id seeded
+-- in 00001; ON DELETE CASCADE is irrelevant here (we only touch its messages).
+
+-- +goose Up
+DELETE FROM backend.ad_messages WHERE campaign_id = '00000000-0000-0000-0000-0000000000ad';
+INSERT INTO backend.ad_messages (message_id, campaign_id, "position", body_en, body_ru) VALUES
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 0, 'Keep a balanced rack — a slight edge of consonants over vowels.', 'Держи на руках баланс — с лёгким перевесом согласных над гласными.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 1, 'Your "leave" (the tiles you keep) sets up your next turn — value it.', '«Остаток» (что оставляешь на руках) готовит следующий ход — цени его.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 2, 'Shed duplicate tiles — repeats clog your options.', 'Сбрасывай дубли фишек — повторы забивают возможности.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 3, 'A slightly consonant-heavy rack builds full-rack plays more easily.', 'Лёгкий перевес согласных проще складывается в выкладку всех фишек.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 4, 'Play several tiles per turn to keep your rack cycling.', 'Выкладывай по нескольку фишек за ход, чтобы рука обновлялась.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 5, 'Don''t hoard hard-to-place duplicates or a lone high-value tile.', 'Не копи труднопристраиваемые дубли или одинокую дорогую фишку.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 6, 'Using all your rack tiles in one move scores a large bonus — chase it.', 'Выкладка всех фишек с рук за ход даёт крупный бонус — стремись к ней.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 7, 'Learn common prefixes and suffixes — they extend words to use every tile.', 'Учи частые приставки и суффиксы — они растягивают слово на все фишки.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 8, '"Fish": play few tiles to keep a near-complete rack when you''re ahead.', '«Рыбачь»: сыграй мало фишек, сохранив почти всю руку, когда ведёшь.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 9, 'Don''t hoard high-value tiles — play them in good time, not at the very end.', 'Не копи дорогие фишки — играй их вовремя, а не под самый конец.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 10, 'Don''t hold a high-value tile waiting for a rare partner — usually a loss.', 'Не держи дорогую фишку ради редкого партнёра — обычно это проигрыш.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 11, 'Land your priciest tile on a premium square for a big single score.', 'Сажай самую дорогую фишку на бонусную клетку ради крупных очков.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 12, 'High-value tiles shine in parallel plays through short words.', 'Дорогие фишки сильны в параллельных выкладках через короткие слова.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 13, 'Stuck with an unplayable high-value tile late? Exchange it.', 'Завис с неиграбельной дорогой фишкой под конец? Обменяй её.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 14, 'The blanks are the most valuable tiles in the bag — guard them.', 'Пустышки — самые ценные фишки в мешке; береги их.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 15, 'Save a blank for a full-rack play or a key premium square.', 'Береги пустышку для выкладки всех фишек или важной бонусной клетки.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 16, 'Don''t spend a blank cheaply — hold it for a much bigger gain.', 'Не трать пустышку по мелочи — придержи ради куда большей выгоды.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 17, 'Put high-value tiles on letter-bonus or word-bonus squares.', 'Клади дорогие фишки на бонус буквы или слова.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 18, 'Stack bonuses — a letter bonus under a word bonus multiplies both.', 'Совмещай бонусы — бонус буквы под бонусом слова умножает оба.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 19, 'Parallel plays can earn nearly half your points — look for them.', 'Параллельные выкладки могут давать почти половину очков — ищи их.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 20, 'A hook adds one tile to an existing word to make a new one.', '«Крючок» — одна фишка к готовому слову, образующая новое.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 21, 'Hooks work at the front or the back of a word.', 'Крючки работают спереди и сзади слова.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 22, 'Short words are the keys to tight parallel plays — memorize them.', 'Короткие слова — ключ к плотным параллелям; выучи их.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 23, 'Your opening word crosses the centre — keep it compact, don''t open up.', 'Первое слово идёт через центр — держи компактным, не раскрывайся.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 24, 'It''s not only your score — limit your opponent''s options too.', 'Это не только твои очки — ограничивай и возможности соперника.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 25, 'Denying a big reply often beats squeezing a few more points yourself.', 'Закрыть крупный ответ часто важнее, чем добрать пару своих очков.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 26, 'When ahead, keep the board tight and closed; avoid open lanes.', 'Ведёшь — держи доску плотной и закрытой, не открывай линии.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 27, 'When behind, open the board up to create high-scoring chances.', 'Отстаёшь — раскрывай доску ради шансов на крупный ход.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 28, 'Don''t leave a word-bonus square open right beside your word.', 'Не оставляй клетку бонуса слова открытой рядом со своим словом.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 29, 'Block a hot square even with a weak word to deny a big play.', 'Закрывай опасную клетку даже слабым словом, чтобы срубить крупный ход.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 30, 'Know words that take no hooks — use them to seal off lines.', 'Знай слова, не берущие крючков — ими запирай линии.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 31, 'Track the tiles played to judge what is still left in the bag.', 'Считай сыгранные фишки — так поймёшь, что осталось в мешке.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 32, 'Exchange when your rack is unbalanced or can only score low.', 'Меняй фишки, когда рука несбалансированна или тянет мало.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 33, 'A good exchange beats a bad play — a clean rack is worth a turn.', 'Хороший обмен лучше плохого хода — чистая рука стоит хода.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 34, 'Swap away a surplus of vowels or consonants to rebalance.', 'Сбрасывай в обмен избыток гласных или согласных, чтобы выровняться.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 35, 'Rare high-value tiles are gone once seen — note them as they appear.', 'Редкие дорогие фишки исчезают, едва мелькнув — отмечай их.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 36, 'Once the bag is empty, deduce your opponent''s remaining tiles.', 'Когда мешок пуст, вычисли оставшиеся фишки соперника.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 37, 'Shed high-value tiles before the bag empties — don''t get stuck with them.', 'Сбрось дорогие фишки до опустения мешка — не зависай с ними.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 38, 'Unplayed tiles count against you at the end — try to go out first.', 'Несыгранные фишки минусуют очки в конце — старайся выйти первым.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 39, 'Going out first adds your opponent''s leftover tiles to your score.', 'Кто вышел первым, добирает очки за оставшиеся фишки соперника.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 40, 'Sometimes leaving one tile in the bag buys you an extra turn.', 'Иногда оставить одну фишку в мешке — это лишний ход.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 41, 'In the endgame, block the exact squares your opponent needs.', 'В эндшпиле блокируй именно те клетки, что нужны сопернику.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 42, 'Shuffle your rack to spot new patterns.', 'Перемешивай фишки на руках — так замечаешь новые сочетания.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 43, 'Separate prefix, suffix and middle tiles to anagram faster.', 'Разнеси приставку, суффикс и середину — анаграммы решаются быстрее.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 44, 'Value board position and future turns over raw points this turn.', 'Цени позицию и будущие ходы выше сиюминутных очков.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 45, 'Early game build position; midgame maximize score; endgame defend.', 'В начале — позиция, в середине — очки, в конце — защита.'),
+    (gen_random_uuid(), '00000000-0000-0000-0000-0000000000ad', 46, 'Learn the short-word lists first — they pay off in every game.', 'Сначала учи списки коротких слов — окупаются в каждой партии.');
+
+-- +goose Down
+-- Restore the original single house tip seeded by the baseline.
+DELETE FROM backend.ad_messages WHERE campaign_id = '00000000-0000-0000-0000-0000000000ad';
+INSERT INTO backend.ad_messages (message_id, campaign_id, "position", body_en, body_ru)
+VALUES ('00000000-0000-0000-0000-0000000000a1', '00000000-0000-0000-0000-0000000000ad', 0,
+    'Tip: a play using all 7 tiles earns a +50 bonus.',
+    'Совет: ход всеми 7 фишками приносит бонус +50 очков.');

backend/internal/postgres/migrations/00003_feedback_app_version.sql

@@ -0,0 +1,10 @@
+-- Capture the client app version (the build a report was sent from) with each feedback
+-- message, so the operator console can show which version a player was on. Nullable, so the
+-- rows that predate this keep working — additive and backward-compatible, so a backend image
+-- rollback stays DB-safe (older code simply ignores the column).
+
+-- +goose Up
+ALTER TABLE backend.feedback_messages ADD COLUMN app_version text;
+
+-- +goose Down
+ALTER TABLE backend.feedback_messages DROP COLUMN app_version;

backend/internal/postgres/migrations/00004_feedback_browser_tz.sql

@@ -0,0 +1,11 @@
+-- Capture the client's detected UTC offset ("±HH:MM") with each feedback message, so the
+-- operator console can show the filed time in the sender's browser-local zone even before that
+-- player has ever saved a profile (the account zone defaults to UTC until then). Nullable, so the
+-- rows that predate this keep working — additive and backward-compatible, so a backend image
+-- rollback stays DB-safe (older code simply ignores the column).
+
+-- +goose Up
+ALTER TABLE backend.feedback_messages ADD COLUMN browser_tz text;
+
+-- +goose Down
+ALTER TABLE backend.feedback_messages DROP COLUMN browser_tz;

backend/internal/postgres/migrations/00005_vk_identity.sql

@@ -0,0 +1,13 @@
+-- Admit the 'vk' platform identity (VK Mini App users) into the identities.kind check
+-- constraint, alongside telegram/email/robot. Expand-contract: widening the allowed set
+-- is backward-compatible, so a backend image rollback stays DB-safe — the older code
+-- simply never writes a 'vk' row. The table shape is unchanged (only the CHECK), so the
+-- generated go-jet model is not regenerated.
+
+-- +goose Up
+ALTER TABLE backend.identities DROP CONSTRAINT identities_kind_chk;
+ALTER TABLE backend.identities ADD CONSTRAINT identities_kind_chk CHECK ((kind = ANY (ARRAY['telegram'::text, 'vk'::text, 'email'::text, 'robot'::text])));
+
+-- +goose Down
+ALTER TABLE backend.identities DROP CONSTRAINT identities_kind_chk;
+ALTER TABLE backend.identities ADD CONSTRAINT identities_kind_chk CHECK ((kind = ANY (ARRAY['telegram'::text, 'email'::text, 'robot'::text])));

backend/internal/postgres/migrations/00006_email_confirm_deeplink.sql

@@ -0,0 +1,27 @@
+-- Add the confirm deeplink token and the confirmation purpose to email_confirmations.
+-- purpose tags what verifying the code/token does (email login, identity link, email
+-- change, or account deletion); link_token_hash holds the SHA-256 hex of the one-click
+-- deeplink token (only the hash is stored, mirroring the session-token model).
+-- Expand-contract: both columns are additive. purpose gets a NOT NULL DEFAULT so
+-- existing rows fill in; link_token_hash is nullable with a partial-unique index. A
+-- backend image rollback stays DB-safe — older code simply ignores the new columns. The
+-- table shape changes, so the generated go-jet model for this table is regenerated.
+
+-- +goose Up
+ALTER TABLE backend.email_confirmations
+    ADD COLUMN purpose text NOT NULL DEFAULT 'link',
+    ADD COLUMN link_token_hash text;
+ALTER TABLE backend.email_confirmations
+    ADD CONSTRAINT email_confirmations_purpose_chk
+        CHECK ((purpose = ANY (ARRAY['login'::text, 'link'::text, 'change'::text, 'delete'::text])));
+CREATE UNIQUE INDEX email_confirmations_link_token_hash_key
+    ON backend.email_confirmations (link_token_hash)
+    WHERE link_token_hash IS NOT NULL;
+
+-- +goose Down
+DROP INDEX IF EXISTS backend.email_confirmations_link_token_hash_key;
+ALTER TABLE backend.email_confirmations
+    DROP CONSTRAINT IF EXISTS email_confirmations_purpose_chk;
+ALTER TABLE backend.email_confirmations
+    DROP COLUMN IF EXISTS link_token_hash,
+    DROP COLUMN IF EXISTS purpose;

backend/internal/postgres/migrations/00007_account_deletion_retention.sql

@@ -0,0 +1,47 @@
+-- Account deletion as legal retention (not erasure). Two additive pieces.
+--
+-- retained_identities is an append-only journal of every credential detached from an
+-- account — on unlink, email change, or account deletion (reason). It preserves the legal
+-- dossier (which email/vk/tg was linked, and when) while the live identities row is
+-- removed, so the (kind, external_id) frees for a new account to reuse. No unique
+-- constraint and no kind CHECK: the same credential may recur across accounts and events,
+-- and the log stays robust to future identity kinds. detached_at drives the retention TTL.
+--
+-- accounts gains: last_login_at / last_login_ip (stamped on a cold app-load, throttled),
+-- deleted_at (the tombstone marker), and deleted_display_name (the real name retained for
+-- the admin dossier after the live display_name is scrubbed to the anonymised label).
+--
+-- Expand-contract: everything is additive (a new table plus nullable columns), so a
+-- backend image rollback stays DB-safe — older code simply ignores them. The accounts
+-- table shape changes, so its generated go-jet model is regenerated.
+
+-- +goose Up
+CREATE TABLE backend.retained_identities (
+    retained_id uuid NOT NULL,
+    account_id uuid NOT NULL,
+    kind text NOT NULL,
+    external_id text NOT NULL,
+    confirmed boolean DEFAULT false NOT NULL,
+    linked_at timestamp with time zone NOT NULL,
+    detached_at timestamp with time zone DEFAULT now() NOT NULL,
+    reason text NOT NULL,
+    CONSTRAINT retained_identities_pkey PRIMARY KEY (retained_id),
+    CONSTRAINT retained_identities_reason_chk
+        CHECK ((reason = ANY (ARRAY['unlink'::text, 'change'::text, 'delete'::text])))
+);
+CREATE INDEX retained_identities_account_id_idx ON backend.retained_identities (account_id);
+CREATE INDEX retained_identities_detached_at_idx ON backend.retained_identities (detached_at);
+
+ALTER TABLE backend.accounts
+    ADD COLUMN last_login_at timestamp with time zone,
+    ADD COLUMN last_login_ip text,
+    ADD COLUMN deleted_at timestamp with time zone,
+    ADD COLUMN deleted_display_name text;
+
+-- +goose Down
+ALTER TABLE backend.accounts
+    DROP COLUMN last_login_at,
+    DROP COLUMN last_login_ip,
+    DROP COLUMN deleted_at,
+    DROP COLUMN deleted_display_name;
+DROP TABLE backend.retained_identities;

backend/internal/postgres/migrations/00008_retained_identities_merge_reason.sql

@@ -0,0 +1,22 @@
+-- Admit the 'merge' reason into retained_identities. An account merge folds a secondary
+-- account into a primary; when both hold an identity of the same kind (e.g. each has a
+-- confirmed email), the survivor keeps its own and the secondary's is journaled to the
+-- legal dossier and removed — so the survivor never ends up with two identities of one
+-- kind, and the absorbed credential is still retained. That journal row carries reason
+-- 'merge', alongside the existing unlink / change / delete.
+--
+-- Expand-contract: the Up only WIDENS the allowed reason set, so an older backend image
+-- (which writes only unlink/change/delete) still satisfies the constraint — a rollback
+-- stays DB-safe. The Down narrows it again and would reject pre-existing 'merge' rows, so
+-- it is a dev-only convenience, not a production rollback path (image rollback runs old
+-- code against this schema, not the Down migration).
+
+-- +goose Up
+ALTER TABLE backend.retained_identities DROP CONSTRAINT retained_identities_reason_chk;
+ALTER TABLE backend.retained_identities ADD CONSTRAINT retained_identities_reason_chk
+    CHECK ((reason = ANY (ARRAY['unlink'::text, 'change'::text, 'delete'::text, 'merge'::text])));
+
+-- +goose Down
+ALTER TABLE backend.retained_identities DROP CONSTRAINT retained_identities_reason_chk;
+ALTER TABLE backend.retained_identities ADD CONSTRAINT retained_identities_reason_chk
+    CHECK ((reason = ANY (ARRAY['unlink'::text, 'change'::text, 'delete'::text])));

backend/internal/render/render.go

@@ -0,0 +1,61 @@
+// Package render is the backend's client for the internal image-render sidecar: it POSTs
+// a finished game's export payload and receives the rasterized PNG. The sidecar runs the
+// same drawing code the web client unit-tests (ui/src/lib/gameimage.ts on skia-canvas);
+// authentication and the signed public URL live in the server layer — this client only
+// carries bytes.
+package render
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+// maxPNG caps a render response; a scale-2 export of the largest plausible game is well
+// under 2 MiB, so anything bigger is a sidecar malfunction, not a valid image.
+const maxPNG = 8 << 20
+
+// Client calls the render sidecar over the internal network.
+type Client struct {
+	base string
+	http *http.Client
+}
+
+// New returns a client for the sidecar at baseURL (e.g. http://renderer:8090). A render
+// of a full game takes well under a second; the timeout leaves room for a cold start.
+func New(baseURL string) *Client {
+	return &Client{base: baseURL, http: &http.Client{Timeout: 15 * time.Second}}
+}
+
+// Render posts payload (the JSON request shape the sidecar consumes) and returns the PNG.
+func (c *Client) Render(ctx context.Context, payload any) ([]byte, error) {
+	body, err := json.Marshal(payload)
+	if err != nil {
+		return nil, fmt.Errorf("render: marshal payload: %w", err)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.base+"/render", bytes.NewReader(body))
+	if err != nil {
+		return nil, fmt.Errorf("render: build request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("render: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("render: sidecar status %d", resp.StatusCode)
+	}
+	png, err := io.ReadAll(io.LimitReader(resp.Body, maxPNG+1))
+	if err != nil {
+		return nil, fmt.Errorf("render: read response: %w", err)
+	}
+	if len(png) > maxPNG {
+		return nil, fmt.Errorf("render: response exceeds %d bytes", maxPNG)
+	}
+	return png, nil
+}

backend/internal/server/banner.go

@@ -45,9 +45,34 @@ type bannerTimingsDTO struct {
 func (s *Server) profileResponse(ctx context.Context, acc account.Account) profileResponse {
 	r := profileResponseFor(acc)
 	r.Banner = s.bannerFor(ctx, acc)
+	s.fillLinkedIdentities(ctx, &r, acc.ID)
 	return r
 }
 
+// fillLinkedIdentities sets the profile's confirmed email address and platform-linked
+// flags from the account's identities, so the client offers the right link / unlink /
+// change-email controls. A read failure leaves them zero (no controls), logged as a
+// warning so the profile response still succeeds.
+func (s *Server) fillLinkedIdentities(ctx context.Context, r *profileResponse, accountID uuid.UUID) {
+	ids, err := s.accounts.Identities(ctx, accountID)
+	if err != nil {
+		s.log.Warn("profile: identities read failed", zap.String("account", accountID.String()), zap.Error(err))
+		return
+	}
+	for _, id := range ids {
+		switch id.Kind {
+		case account.KindEmail:
+			if id.Confirmed {
+				r.Email = id.ExternalID
+			}
+		case account.KindTelegram:
+			r.TelegramLinked = true
+		case account.KindVK:
+			r.VkLinked = true
+		}
+	}
+}
+
 // bannerFor builds the advertising-banner block for the account's profile, or
 // nil when the ads service is not configured or the viewer is not eligible to
 // see a banner. The message language follows the account's bot (service)

backend/internal/server/dto.go

@@ -56,6 +56,13 @@ type profileResponse struct {
 	// see the banner (a free account with an empty hint wallet and without the
 	// no_banner role), absent otherwise. See banner.go.
 	Banner *bannerDTO `json:"banner,omitempty"`
+	// Email is the account's confirmed email address ("" when none); TelegramLinked and
+	// VkLinked report whether a platform identity is attached. They drive the profile's
+	// link / unlink / change-email controls, and are filled outside the pure projection
+	// (they read the account's identities). See Server.profileResponse.
+	Email          string `json:"email"`
+	TelegramLinked bool   `json:"telegram_linked"`
+	VkLinked       bool   `json:"vk_linked"`
 }
 
 // tileDTO is one placed (or to-place) tile.

backend/internal/server/dto_test.go

@@ -30,6 +30,7 @@ func TestStatusForError(t *testing.T) {
 		"illegal play":   {engine.ErrIllegalPlay, http.StatusUnprocessableEntity, "illegal_play"},
 		"email taken":    {account.ErrEmailTaken, http.StatusConflict, "email_taken"},
 		"code mismatch":  {account.ErrCodeMismatch, http.StatusUnauthorized, "code_invalid"},
+		"too many codes": {account.ErrTooManyRequests, http.StatusTooManyRequests, "too_many_requests"},
 		"session gone":   {session.ErrNotFound, http.StatusUnauthorized, "session_invalid"},
 		"chat forbidden": {social.ErrForbiddenContent, http.StatusUnprocessableEntity, "chat_rejected"},
 		"no hint move":   {game.ErrNoHintAvailable, http.StatusConflict, "no_hint_available"},

backend/internal/server/export.go

@@ -0,0 +1,310 @@
+// Finished-game export downloads: a signed, short-lived, relative URL minted for a
+// participant and later fetched with no credentials at all — the platforms' native
+// download calls (Telegram downloadFile, VKWebAppDownloadFile, a plain browser
+// anchor) strip cookies and headers, so the HMAC in the URL is the whole grant.
+// The client resolves the relative path against its own origin; the edge routes
+// /dl/* to the gateway, which forwards it here (/api/v1/public/dl/...).
+package server
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
+)
+
+// exportURLTTL is how long a minted download URL stays valid. Long enough for the
+// platform's download dialog and a retry, short enough that a leaked link dies fast.
+const exportURLTTL = 10 * time.Minute
+
+// Query/label size caps: the presentation params ride the signed URL, so they are
+// bounded defensively (they only ever hold a BCP-47 tag and four short UI words).
+const (
+	maxDateLocaleLen = 35
+	maxLabelsLen     = 120
+	maxTimeZoneLen   = 50
+)
+
+// exportActionOrder fixes the position of each non-play move label in the `t` CSV.
+var exportActionOrder = [4]string{"pass", "exchange", "resign", "timeout"}
+
+// signExport computes the URL signature over the canonical parameter string. The
+// canonical form is independent of the public path prefix, so the gateway may mount
+// the route anywhere.
+func (s *Server) signExport(gameID, kind, exp, dateLocale, timeZone, labels string) string {
+	mac := hmac.New(sha256.New, s.exportKey)
+	fmt.Fprintf(mac, "%s|%s|%s|%s|%s|%s", gameID, kind, exp, dateLocale, timeZone, labels)
+	return base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
+}
+
+// exportURLDTO is the minted link: a relative signed path plus the download filename.
+type exportURLDTO struct {
+	Path     string `json:"path"`
+	Filename string `json:"filename"`
+}
+
+// handleExportURL mints the signed download path for a finished game's artifact.
+// GET /api/v1/user/games/:id/export-url?kind=png|gcg&dl=<date-locale>&tz=<IANA zone>&t=<labels CSV>
+func (s *Server) handleExportURL(c *gin.Context) {
+	if len(s.exportKey) == 0 {
+		c.AbortWithStatusJSON(http.StatusServiceUnavailable,
+			errorResponse{Error: errorBody{Code: "export_unavailable", Message: "export signing is not configured"}})
+		return
+	}
+	_, gameID, ok := s.userGame(c)
+	if !ok {
+		return
+	}
+	kind := c.Query("kind")
+	if kind != "png" && kind != "gcg" {
+		abortBadRequest(c, "invalid kind")
+		return
+	}
+	dateLocale := c.Query("dl")
+	timeZone := c.Query("tz")
+	labels := c.Query("t")
+	if len(dateLocale) > maxDateLocaleLen || len(labels) > maxLabelsLen || len(timeZone) > maxTimeZoneLen {
+		abortBadRequest(c, "presentation params too long")
+		return
+	}
+	if err := s.games.EnsureExportable(c.Request.Context(), gameID); err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	exp := strconv.FormatInt(time.Now().Add(exportURLTTL).Unix(), 10)
+	sig := s.signExport(gameID.String(), kind, exp, dateLocale, timeZone, labels)
+	q := url.Values{"e": {exp}, "s": {sig}}
+	if dateLocale != "" {
+		q.Set("l", dateLocale)
+	}
+	if timeZone != "" {
+		q.Set("z", timeZone)
+	}
+	if labels != "" {
+		q.Set("t", labels)
+	}
+	c.JSON(http.StatusOK, exportURLDTO{
+		Path:     "/dl/" + gameID.String() + "/" + kind + "?" + q.Encode(),
+		Filename: exportFilename(gameID, kind),
+	})
+}
+
+func exportFilename(gameID uuid.UUID, kind string) string {
+	return "game-" + gameID.String()[:8] + "." + kind
+}
+
+// handleExportDownload serves a minted artifact. It is a public route: the signature
+// and expiry are the only authorization (see the package comment). Every failure is
+// a plain 404 so the endpoint is not a validity oracle.
+// GET /api/v1/public/dl/:id/:kind?e=&l=&z=&t=&s=
+func (s *Server) handleExportDownload(c *gin.Context) {
+	if len(s.exportKey) == 0 {
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+	gameID, err := uuid.Parse(c.Param("id"))
+	kind := c.Param("kind")
+	exp := c.Query("e")
+	dateLocale := c.Query("l")
+	timeZone := c.Query("z")
+	labels := c.Query("t")
+	sig := c.Query("s")
+	if err != nil || (kind != "png" && kind != "gcg") ||
+		len(dateLocale) > maxDateLocaleLen || len(labels) > maxLabelsLen || len(timeZone) > maxTimeZoneLen {
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+	want := s.signExport(gameID.String(), kind, exp, dateLocale, timeZone, labels)
+	if subtleNeq(sig, want) {
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+	if unix, err := strconv.ParseInt(exp, 10, 64); err != nil || time.Now().Unix() > unix {
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+
+	filename := exportFilename(gameID, kind)
+	if kind == "gcg" {
+		gcg, err := s.games.ExportGCG(c.Request.Context(), gameID)
+		if err != nil {
+			c.String(http.StatusNotFound, "not found")
+			return
+		}
+		serveAttachment(c, filename, "text/plain; charset=utf-8", []byte(gcg))
+		return
+	}
+
+	if s.renderer == nil {
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+	g, moves, names, err := s.games.ExportView(c.Request.Context(), gameID)
+	if err != nil {
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+	payload, err := renderPayload(g, moves, names, dateLocale, timeZone, labels, c.GetHeader("X-Public-Host"))
+	if err != nil {
+		s.log.Warn("export render payload", zap.Error(err))
+		c.String(http.StatusNotFound, "not found")
+		return
+	}
+	png, err := s.renderer.Render(c.Request.Context(), payload)
+	if err != nil {
+		s.log.Warn("export render", zap.Error(err))
+		c.String(http.StatusServiceUnavailable, "render unavailable")
+		return
+	}
+	serveAttachment(c, filename, "image/png", png)
+}
+
+// subtleNeq compares two signature strings in constant time.
+func subtleNeq(got, want string) bool {
+	return !hmac.Equal([]byte(got), []byte(want))
+}
+
+// serveAttachment writes bytes as a named file download. Content-Length is set
+// explicitly: a body over net/http's write buffer otherwise goes out chunked, and
+// Android's system DownloadManager (which VKWebAppDownloadFile delegates to) hangs
+// forever on a download of unknown length.
+func serveAttachment(c *gin.Context, filename, contentType string, data []byte) {
+	c.Header("X-Content-Type-Options", "nosniff")
+	c.Header("Content-Disposition", `attachment; filename="`+sanitizeFilename(filename)+`"`)
+	c.Header("Cache-Control", "private, max-age=0")
+	c.Header("Content-Length", strconv.Itoa(len(data)))
+	c.Data(http.StatusOK, contentType, data)
+}
+
+// --- the render-sidecar request payload (the ui-model shapes drawGameImage consumes) ---
+
+type renderSeatJSON struct {
+	Seat        int    `json:"seat"`
+	AccountID   string `json:"accountId"`
+	DisplayName string `json:"displayName"`
+	Score       int    `json:"score"`
+	HintsUsed   int    `json:"hintsUsed"`
+	IsWinner    bool   `json:"isWinner"`
+}
+
+type renderGameJSON struct {
+	ID               string           `json:"id"`
+	Variant          string           `json:"variant"`
+	Status           string           `json:"status"`
+	Players          int              `json:"players"`
+	LastActivityUnix int64            `json:"lastActivityUnix"`
+	Seats            []renderSeatJSON `json:"seats"`
+}
+
+type renderTileJSON struct {
+	Row    int    `json:"row"`
+	Col    int    `json:"col"`
+	Letter string `json:"letter"`
+	Blank  bool   `json:"blank"`
+}
+
+type renderMoveJSON struct {
+	Player  int              `json:"player"`
+	Action  string           `json:"action"`
+	Dir     string           `json:"dir"`
+	MainRow int              `json:"mainRow"`
+	MainCol int              `json:"mainCol"`
+	Tiles   []renderTileJSON `json:"tiles"`
+	Words   []string         `json:"words"`
+	Count   int              `json:"count"`
+	Score   int              `json:"score"`
+	Total   int              `json:"total"`
+}
+
+type renderAlphaJSON struct {
+	Index  int    `json:"index"`
+	Letter string `json:"letter"`
+	Value  int    `json:"value"`
+}
+
+type renderRequestJSON struct {
+	Game       renderGameJSON    `json:"game"`
+	Moves      []renderMoveJSON  `json:"moves"`
+	Alphabet   []renderAlphaJSON `json:"alphabet"`
+	Labels     map[string]string `json:"labels"`
+	DateLocale string            `json:"dateLocale"`
+	TimeZone   string            `json:"timeZone"`
+	Hostname   string            `json:"hostname"`
+}
+
+// renderPayload assembles the sidecar request from the export view. Letters are
+// upper-cased for display exactly as the client codec does; the localized non-play
+// labels arrive as a positional CSV (see exportActionOrder) minted into the URL.
+func renderPayload(g game.Game, moves []game.HistoryMove, names []string, dateLocale, timeZone, labelsCSV, host string) (renderRequestJSON, error) {
+	alpha, err := engine.AlphabetTable(g.Variant)
+	if err != nil {
+		return renderRequestJSON{}, fmt.Errorf("alphabet for %s: %w", g.Variant, err)
+	}
+	req := renderRequestJSON{
+		Game: renderGameJSON{
+			ID:      g.ID.String(),
+			Variant: g.Variant.String(),
+			Status:  g.Status,
+			Players: g.Players,
+		},
+		Labels:     map[string]string{},
+		DateLocale: dateLocale,
+		TimeZone:   timeZone,
+		Hostname:   host,
+	}
+	finished := g.UpdatedAt
+	if g.FinishedAt != nil {
+		finished = *g.FinishedAt
+	}
+	req.Game.LastActivityUnix = finished.Unix()
+	for _, st := range g.Seats {
+		name := st.DisplayName
+		if st.Seat < len(names) {
+			name = names[st.Seat]
+		}
+		req.Game.Seats = append(req.Game.Seats, renderSeatJSON{
+			Seat: st.Seat, AccountID: st.AccountID.String(), DisplayName: name,
+			Score: st.Score, HintsUsed: st.HintsUsed, IsWinner: st.IsWinner,
+		})
+	}
+	for _, m := range moves {
+		mv := renderMoveJSON{
+			Player: m.Seat, Action: m.Action, Dir: m.Dir,
+			MainRow: m.MainRow, MainCol: m.MainCol,
+			Words: make([]string, 0, len(m.Words)),
+			Count: len(m.Exchanged), Score: m.Score, Total: m.RunningTotal,
+			Tiles: make([]renderTileJSON, 0, len(m.Tiles)),
+		}
+		for _, w := range m.Words {
+			mv.Words = append(mv.Words, strings.ToUpper(w))
+		}
+		for _, t := range m.Tiles {
+			mv.Tiles = append(mv.Tiles, renderTileJSON{Row: t.Row, Col: t.Col, Letter: strings.ToUpper(t.Letter), Blank: t.Blank})
+		}
+		req.Moves = append(req.Moves, mv)
+	}
+	for _, a := range alpha {
+		req.Alphabet = append(req.Alphabet, renderAlphaJSON{Index: int(a.Index), Letter: strings.ToUpper(a.Letter), Value: a.Value})
+	}
+	if labelsCSV != "" {
+		parts := strings.Split(labelsCSV, ",")
+		for i, action := range exportActionOrder {
+			if i < len(parts) && parts[i] != "" {
+				req.Labels[action] = parts[i]
+			}
+		}
+	}
+	return req, nil
+}

backend/internal/server/export_test.go

@@ -0,0 +1,148 @@
+package server
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+
+	"scrabble/backend/internal/account"
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
+	"scrabble/backend/internal/session"
+)
+
+// newExportServer is the routing harness with a signing key installed, so the
+// pre-service branches of the export endpoints are reachable.
+func newExportServer() *Server {
+	return New(":0", Deps{
+		Sessions:      &session.Service{},
+		Accounts:      &account.Store{},
+		Games:         &game.Service{},
+		ExportSignKey: "test-key",
+	})
+}
+
+func TestSignExportIsDeterministicAndTamperEvident(t *testing.T) {
+	s := newExportServer()
+	sig := s.signExport("g1", "png", "123", "ru", "Europe/Moscow", "пас,обмен")
+	if sig != s.signExport("g1", "png", "123", "ru", "Europe/Moscow", "пас,обмен") {
+		t.Fatal("same inputs produced different signatures")
+	}
+	for _, tampered := range []string{
+		s.signExport("g2", "png", "123", "ru", "Europe/Moscow", "пас,обмен"),
+		s.signExport("g1", "gcg", "123", "ru", "Europe/Moscow", "пас,обмен"),
+		s.signExport("g1", "png", "124", "ru", "Europe/Moscow", "пас,обмен"),
+		s.signExport("g1", "png", "123", "en", "Europe/Moscow", "пас,обмен"),
+		s.signExport("g1", "png", "123", "ru", "UTC", "пас,обмен"),
+		s.signExport("g1", "png", "123", "ru", "Europe/Moscow", "пас"),
+	} {
+		if tampered == sig {
+			t.Fatal("tampered input produced the same signature")
+		}
+	}
+}
+
+func TestExportURLWithoutKeyIs503(t *testing.T) {
+	s := New(":0", Deps{Sessions: &session.Service{}, Accounts: &account.Store{}, Games: &game.Service{}})
+	rec := do(t, s, http.MethodGet, "/api/v1/user/games/"+uuid.NewString()+"/export-url?kind=png", "",
+		map[string]string{"X-User-ID": uuid.NewString()})
+	if rec.Code != http.StatusServiceUnavailable {
+		t.Fatalf("mint without key = %d, want 503", rec.Code)
+	}
+}
+
+func TestExportURLRejectsBadParams(t *testing.T) {
+	s := newExportServer()
+	uid := map[string]string{"X-User-ID": uuid.NewString()}
+	gid := uuid.NewString()
+
+	if rec := do(t, s, http.MethodGet, "/api/v1/user/games/"+gid+"/export-url?kind=exe", "", uid); rec.Code != http.StatusBadRequest {
+		t.Fatalf("bad kind = %d, want 400", rec.Code)
+	}
+	long := strings.Repeat("x", maxLabelsLen+1)
+	if rec := do(t, s, http.MethodGet, "/api/v1/user/games/"+gid+"/export-url?kind=png&t="+long, "", uid); rec.Code != http.StatusBadRequest {
+		t.Fatalf("oversized labels = %d, want 400", rec.Code)
+	}
+}
+
+func TestExportDownloadRejectsBadSignatures(t *testing.T) {
+	s := newExportServer()
+	gid := uuid.NewString()
+	exp := strconv.FormatInt(time.Now().Add(time.Minute).Unix(), 10)
+
+	// A wrong signature never reaches the domain (404 before any service call).
+	url := "/api/v1/public/dl/" + gid + "/png?e=" + exp + "&s=forged"
+	if rec := do(t, s, http.MethodGet, url, "", nil); rec.Code != http.StatusNotFound {
+		t.Fatalf("forged signature = %d, want 404", rec.Code)
+	}
+
+	// A valid signature over an EXPIRED timestamp is refused the same way.
+	old := strconv.FormatInt(time.Now().Add(-time.Minute).Unix(), 10)
+	url = "/api/v1/public/dl/" + gid + "/png?e=" + old + "&s=" + s.signExport(gid, "png", old, "", "", "")
+	if rec := do(t, s, http.MethodGet, url, "", nil); rec.Code != http.StatusNotFound {
+		t.Fatalf("expired link = %d, want 404", rec.Code)
+	}
+
+	// An unknown kind is refused before signature checks.
+	url = "/api/v1/public/dl/" + gid + "/exe?e=" + exp + "&s=x"
+	if rec := do(t, s, http.MethodGet, url, "", nil); rec.Code != http.StatusNotFound {
+		t.Fatalf("bad kind = %d, want 404", rec.Code)
+	}
+}
+
+func TestRenderPayloadMapsTheExportView(t *testing.T) {
+	gid := uuid.New()
+	finished := time.Unix(1_782_997_629, 0)
+	g := game.Game{
+		ID:         gid,
+		Variant:    engine.VariantRussianScrabble,
+		Status:     game.StatusFinished,
+		Players:    2,
+		FinishedAt: &finished,
+		Seats: []game.Seat{
+			{Seat: 0, Score: 42, IsWinner: true, DisplayName: "snapshot"},
+			{Seat: 1, Score: 30},
+		},
+	}
+	moves := []game.HistoryMove{
+		{
+			Seat: 0, Action: "play", Dir: "H", MainRow: 7, MainCol: 4,
+			Tiles: []engine.TileRecord{{Row: 7, Col: 4, Letter: "ч", Blank: false}},
+			Words: []string{"чика"}, Score: 9, RunningTotal: 9,
+		},
+		{Seat: 1, Action: "exchange", Exchanged: []string{"а", "б"}, RunningTotal: 0},
+	}
+	names := []string{"Аня", "Боб"}
+
+	p, err := renderPayload(g, moves, names, "ru", "Europe/Moscow", "пас,обмен,сдался,таймаут", "erudit-game.ru")
+	if err != nil {
+		t.Fatalf("renderPayload: %v", err)
+	}
+	if p.Game.LastActivityUnix != finished.Unix() {
+		t.Fatalf("lastActivityUnix = %d, want %d", p.Game.LastActivityUnix, finished.Unix())
+	}
+	if p.Game.Seats[0].DisplayName != "Аня" || !p.Game.Seats[0].IsWinner {
+		t.Fatalf("seat 0 = %+v, want the resolved name and the winner flag", p.Game.Seats[0])
+	}
+	if p.Moves[0].Words[0] != "ЧИКА" || p.Moves[0].Tiles[0].Letter != "Ч" {
+		t.Fatalf("letters not upper-cased: %+v", p.Moves[0])
+	}
+	if p.Moves[1].Count != 2 {
+		t.Fatalf("exchange count = %d, want 2", p.Moves[1].Count)
+	}
+	if p.Labels["pass"] != "пас" || p.Labels["timeout"] != "таймаут" {
+		t.Fatalf("labels not mapped positionally: %v", p.Labels)
+	}
+	if len(p.Alphabet) == 0 || p.Hostname != "erudit-game.ru" || p.TimeZone != "Europe/Moscow" {
+		t.Fatalf("alphabet/hostname/zone missing: %d entries, host %q, tz %q", len(p.Alphabet), p.Hostname, p.TimeZone)
+	}
+	for _, a := range p.Alphabet {
+		if a.Letter != strings.ToUpper(a.Letter) {
+			t.Fatalf("alphabet letter %q not upper-cased", a.Letter)
+		}
+	}
+}

backend/internal/server/handlers.go

@@ -27,9 +27,11 @@ func (s *Server) registerRoutes() {
 	if s.sessions != nil && s.accounts != nil {
 		in := s.internal
 		in.POST("/sessions/telegram", s.handleTelegramAuth)
+		in.POST("/sessions/vk", s.handleVKAuth)
 		in.POST("/sessions/guest", s.handleGuestAuth)
 		in.POST("/sessions/email/request", s.handleEmailRequest)
 		in.POST("/sessions/email/login", s.handleEmailLogin)
+		in.POST("/sessions/email/confirm-link", s.handleEmailConfirmLink)
 		in.POST("/sessions/resolve", s.handleResolveSession)
 		in.POST("/sessions/revoke", s.handleRevokeSession)
 		// Out-of-app push routing for the platform side-service: the
@@ -72,6 +74,18 @@ func (s *Server) registerRoutes() {
 		u.POST("/link/email/merge", s.handleLinkEmailMerge)
 		u.POST("/link/telegram", s.handleLinkTelegram)
 		u.POST("/link/telegram/merge", s.handleLinkTelegramMerge)
+		u.POST("/link/vk", s.handleLinkVK)
+		u.POST("/link/vk/merge", s.handleLinkVKMerge)
+		u.POST("/link/unlink", s.handleUnlink)
+		// Change the account's confirmed email: mail a code to the new address, then
+		// atomically switch on confirm (a new address owned by another account is
+		// refused without disclosure, never merged).
+		u.POST("/link/email/change/request", s.handleChangeEmailRequest)
+		u.POST("/link/email/change/confirm", s.handleChangeEmailConfirm)
+		// Account deletion (legal retention, not erasure): step-up via a mailed code
+		// (email accounts) or a typed phrase (platform-only), then tombstone + free creds.
+		u.POST("/delete/request", s.handleRequestDelete)
+		u.POST("/delete/confirm", s.handleConfirmDelete)
 	}
 	if s.games != nil {
 		u.GET("/games", s.handleListGames)
@@ -86,9 +100,17 @@ func (s *Server) registerRoutes() {
 		u.POST("/games/:id/complaint", s.handleComplaint)
 		u.GET("/games/:id/history", s.handleHistory)
 		u.GET("/games/:id/gcg", s.handleExportGCG)
+		u.GET("/games/:id/export-url", s.handleExportURL)
 		u.GET("/games/:id/draft", s.handleGetDraft)
 		u.PUT("/games/:id/draft", s.handleSaveDraft)
 		u.POST("/games/:id/hide", s.handleHideGame)
+		// Raw dictionary download for the client-side local move preview, keyed by
+		// the game's pinned (variant, version); immutable, so cached hard.
+		u.GET("/dict/:variant/:version", s.handleDictBytes)
+		// The signed finished-game export download — the only public data route:
+		// the URL's HMAC + expiry are the whole grant (export.go), because the
+		// platforms' native download calls carry no credentials.
+		s.public.GET("/dl/:id/:kind", s.handleExportDownload)
 	}
 	if s.feedback != nil {
 		u.POST("/feedback", s.handleFeedbackSubmit)
@@ -221,6 +243,8 @@ func statusForError(err error) (int, string) {
 		return http.StatusUnprocessableEntity, "illegal_play"
 	case errors.Is(err, account.ErrEmailTaken), errors.Is(err, account.ErrIdentityTaken):
 		return http.StatusConflict, "email_taken"
+	case errors.Is(err, account.ErrLastIdentity):
+		return http.StatusConflict, "last_identity"
 	case errors.Is(err, accountmerge.ErrActiveGameConflict):
 		return http.StatusConflict, "merge_active_game_conflict"
 	case errors.Is(err, account.ErrInvalidEmail):
@@ -228,6 +252,8 @@ func statusForError(err error) (int, string) {
 	case errors.Is(err, account.ErrCodeMismatch), errors.Is(err, account.ErrCodeExpired),
 		errors.Is(err, account.ErrNoPendingCode), errors.Is(err, account.ErrTooManyAttempts):
 		return http.StatusUnauthorized, "code_invalid"
+	case errors.Is(err, account.ErrTooManyRequests):
+		return http.StatusTooManyRequests, "too_many_requests"
 	case errors.Is(err, session.ErrNotFound):
 		return http.StatusUnauthorized, "session_invalid"
 	case errors.Is(err, social.ErrChatBlocked), errors.Is(err, social.ErrMessageTooLong),

backend/internal/server/handlers_admin_console.go

@@ -61,6 +61,8 @@ func (s *Server) registerConsole(router *gin.Engine) {
 	gm.POST("/users/:id/unblock", s.consoleUnblockUser)
 	gm.POST("/users/:id/grant-role", s.consoleGrantRole)
 	gm.POST("/users/:id/revoke-role", s.consoleRevokeRole)
+	gm.POST("/users/:id/remove-email", s.consoleRemoveEmail)
+	gm.POST("/users/:id/delete", s.consoleDeleteUser)
 	gm.GET("/reasons", s.consoleReasons)
 	gm.POST("/reasons", s.consoleCreateReason)
 	gm.POST("/reasons/:id/update", s.consoleUpdateReason)
@@ -132,8 +134,10 @@ func (s *Server) consoleUsers(c *gin.Context) {
 	page := consolePage(c)
 	filter := account.UserFilter{
 		Robots:         c.Query("kind") == "robots",
+		Deleted:        c.Query("kind") == "deleted",
 		NameMask:       c.Query("name"),
 		ExternalIDMask: c.Query("ext"),
+		EmailExact:     c.Query("email"),
 	}
 	total, _ := s.accounts.CountUsers(ctx, filter)
 	items, err := s.accounts.ListUsers(ctx, filter, adminPageSize, (page-1)*adminPageSize)
@@ -145,28 +149,38 @@ func (s *Server) consoleUsers(c *gin.Context) {
 	if filter.Robots {
 		q.Set("kind", "robots")
 	}
+	if filter.Deleted {
+		q.Set("kind", "deleted")
+	}
 	if strings.TrimSpace(filter.NameMask) != "" {
 		q.Set("name", filter.NameMask)
 	}
 	if strings.TrimSpace(filter.ExternalIDMask) != "" {
 		q.Set("ext", filter.ExternalIDMask)
 	}
+	if strings.TrimSpace(filter.EmailExact) != "" {
+		q.Set("email", filter.EmailExact)
+	}
 	view := adminconsole.UsersView{
 		Pager:  adminconsole.NewPager(page, adminPageSize, total),
-		Robots: filter.Robots, NameMask: filter.NameMask, ExternalIDMask: filter.ExternalIDMask,
+		Robots: filter.Robots, Deleted: filter.Deleted, NameMask: filter.NameMask, ExternalIDMask: filter.ExternalIDMask,
+		EmailExact:  filter.EmailExact,
 		FilterQuery: template.URL(q.Encode()),
 	}
 	ids := make([]uuid.UUID, 0, len(items))
 	for _, it := range items {
 		kind := "registered"
-		if it.IsRobot {
+		switch {
+		case it.IsRobot:
 			kind = "robot"
-		} else if it.IsGuest {
+		case it.IsDeleted:
+			kind = "deleted"
+		case it.IsGuest:
 			kind = "guest"
 		}
 		view.Items = append(view.Items, adminconsole.UserRow{
 			ID: it.ID.String(), DisplayName: it.DisplayName, Kind: kind,
-			Language: it.PreferredLanguage, Guest: it.IsGuest,
+			Language: it.PreferredLanguage, Guest: it.IsGuest, Deleted: it.IsDeleted,
 			FlaggedHighRate: !it.FlaggedHighRateAt.IsZero(), CreatedAt: fmtTime(it.CreatedAt),
 		})
 		ids = append(ids, it.ID)
@@ -356,12 +370,37 @@ func (s *Server) consoleUserDetail(c *gin.Context) {
 	}
 	if ids, err := s.accounts.Identities(ctx, id); err == nil {
 		for _, idn := range ids {
+			if idn.Kind == account.KindEmail {
+				view.HasEmail = true
+			}
 			view.Identities = append(view.Identities, adminconsole.IdentityRow{Kind: idn.Kind, ExternalID: idn.ExternalID, Confirmed: idn.Confirmed, CreatedAt: fmtTime(idn.CreatedAt)})
 		}
 	}
+	if info, err := s.accounts.DeletionInfo(ctx, id); err == nil {
+		if info.LastLoginAt != nil {
+			view.LastLoginAt = fmtTime(*info.LastLoginAt)
+		}
+		view.LastLoginIP = info.LastLoginIP
+		if info.DeletedAt != nil {
+			view.Deleted = true
+			view.DeletedAt = fmtTime(*info.DeletedAt)
+			view.DeletedName = info.DeletedDisplayName
+		}
+	}
+	if rets, err := s.accounts.RetainedIdentities(ctx, id); err == nil {
+		for _, r := range rets {
+			view.Retained = append(view.Retained, adminconsole.RetainedRow{
+				Kind: r.Kind, ExternalID: r.ExternalID, Reason: r.Reason,
+				Confirmed: r.Confirmed, LinkedAt: fmtTime(r.LinkedAt), DetachedAt: fmtTime(r.DetachedAt),
+			})
+		}
+	}
 	if tg, err := s.accounts.IdentityExternalID(ctx, id, account.KindTelegram); err == nil {
 		view.TelegramID = tg
 	}
+	if vk, err := s.accounts.IdentityExternalID(ctx, id, account.KindVK); err == nil {
+		view.VKID = vk
+	}
 	if games, err := s.games.ListForAccount(ctx, id); err == nil {
 		for _, g := range games {
 			view.Games = append(view.Games, gameRow(g))
@@ -948,6 +987,41 @@ func (s *Server) consoleGrantHints(c *gin.Context) {
 	s.renderConsoleMessage(c, "Granted", fmt.Sprintf("added %d hint(s); the wallet is now %d", n, balance), back)
 }
 
+// consoleRemoveEmail deletes the account's bound email identity (and any pending
+// confirmations), freeing the address. It refuses to remove the account's only
+// identity, which would leave it unreachable.
+func (s *Server) consoleRemoveEmail(c *gin.Context) {
+	id, ok := s.consoleUUID(c, "/_gm/users")
+	if !ok {
+		return
+	}
+	back := "/_gm/users/" + id.String()
+	switch err := s.accounts.RemoveEmailIdentity(c.Request.Context(), id); {
+	case errors.Is(err, account.ErrLastIdentity):
+		s.renderConsoleMessage(c, "Can't remove", "the email is this account's only identity — removing it would leave the account unreachable", back)
+	case err != nil:
+		s.consoleError(c, err)
+	default:
+		s.renderConsoleMessage(c, "Removed", "the email identity was erased and the address freed", back)
+	}
+}
+
+// consoleDeleteUser deletes an account from the console — the operator-initiated equivalent
+// of the in-app deletion (legal retention, not erasure): the account is tombstoned, its
+// credentials journalled + freed, its live surfaces anonymised, and its sessions revoked.
+func (s *Server) consoleDeleteUser(c *gin.Context) {
+	id, ok := s.consoleUUID(c, "/_gm/users")
+	if !ok {
+		return
+	}
+	back := "/_gm/users/" + id.String()
+	if err := s.deleteAccount(c.Request.Context(), id); err != nil {
+		s.consoleError(c, err)
+		return
+	}
+	s.renderConsoleMessage(c, "Deleted", "the account was deleted: its credentials were journalled and freed, its data anonymised, and its sessions revoked", back)
+}
+
 // consoleBlockUser manually blocks an account: it records the suspension (permanent or until a
 // parsed deadline, snapshotting the chosen reason's en/ru text) and forfeits the player's active
 // games, removing them from matchmaking. The block takes effect on the player's next request.
@@ -1198,6 +1272,17 @@ func fmtTime(t time.Time) string {
 	return t.UTC().Format("2006-01-02 15:04")
 }
 
+// fmtTimeIn formats a timestamp in the given zone — a "±HH:MM" offset or an IANA name, resolved
+// by account.ResolveZone (falling back to UTC when empty or unknown) — or "" when zero. Used to
+// show a time in a user's local zone beside UTC; the offset form is what the profile editor and
+// the feedback browser-tz snapshot store, so it must not go through time.LoadLocation alone.
+func fmtTimeIn(t time.Time, tz string) string {
+	if t.IsZero() {
+		return ""
+	}
+	return t.In(account.ResolveZone(tz)).Format("2006-01-02 15:04")
+}
+
 // fmtTimePtr formats an optional timestamp for display, or "" when nil.
 func fmtTimePtr(t *time.Time) string {
 	if t == nil {

backend/internal/server/handlers_admin_feedback.go

@@ -77,6 +77,17 @@ func (s *Server) consoleFeedbackDetail(c *gin.Context) {
 		s.consoleError(c, err)
 		return
 	}
+	// Filed time in three zones so the operator can tell what is certainly known from what is
+	// merely defaulted: always UTC; the client's offset detected at submit (when the build
+	// reported one); and the sender's saved profile zone (when set beyond the UTC default). An
+	// empty rendered time makes the template show "N/A" for that line.
+	browserCreated, userCreated := "", ""
+	if m.BrowserTZ != "" {
+		browserCreated = fmtTimeIn(m.CreatedAt, m.BrowserTZ)
+	}
+	if m.TimeZone != "" && m.TimeZone != "UTC" {
+		userCreated = fmtTimeIn(m.CreatedAt, m.TimeZone)
+	}
 	view := adminconsole.FeedbackDetailView{
 		ID: m.ID.String(), AccountID: m.AccountID.String(), SenderName: m.SenderName,
 		Source: m.Source, Channel: m.Channel, InterfaceLanguage: m.Lang,
@@ -84,6 +95,9 @@ func (s *Server) consoleFeedbackDetail(c *gin.Context) {
 		HasAttachment: m.HasAttachment, AttachmentName: m.AttachmentName, IsImage: feedback.IsImage(m.AttachmentName),
 		Read: m.Read, Archived: m.Archived, Replied: m.Replied, ReplyBody: m.ReplyBody,
 		RepliedAt: fmtTime(m.RepliedAt), CreatedAt: fmtTime(m.CreatedAt),
+		Version:          m.Version,
+		CreatedAtBrowser: browserCreated, BrowserTZ: m.BrowserTZ,
+		CreatedAtUser: userCreated, UserTZ: m.TimeZone,
 	}
 	if banned, err := s.accounts.HasRole(ctx, m.AccountID, account.RoleFeedbackBanned); err == nil {
 		view.Banned = banned

backend/internal/server/handlers_auth.go

@@ -6,8 +6,10 @@ import (
 
 	"github.com/gin-gonic/gin"
 	"github.com/google/uuid"
+	"go.uber.org/zap"
 
 	"scrabble/backend/internal/account"
+	"scrabble/backend/internal/notify"
 )
 
 // The /api/v1/internal/sessions/* endpoints are gateway-only: the gateway has
@@ -18,12 +20,17 @@ import (
 
 // telegramAuthRequest carries the identity the connector extracted from a
 // validated initData payload. Username, FirstName and LanguageCode seed a
-// brand-new account's display name and language (first contact only).
+// brand-new account's display name and language; BrowserTZ (the client's detected
+// "±HH:MM" UTC offset) seeds its time zone; StartParam is the validated launch
+// deep-link payload, which may seed the new account's variant preferences (first
+// contact only).
 type telegramAuthRequest struct {
 	ExternalID   string `json:"external_id"`
 	Username     string `json:"username"`
 	FirstName    string `json:"first_name"`
 	LanguageCode string `json:"language_code"`
+	BrowserTZ    string `json:"browser_tz"`
+	StartParam   string `json:"start_param"`
 }
 
 // handleTelegramAuth provisions (or finds) the account bound to a Telegram
@@ -35,7 +42,7 @@ func (s *Server) handleTelegramAuth(c *gin.Context) {
 		abortBadRequest(c, "external_id is required")
 		return
 	}
-	acc, created, err := s.accounts.ProvisionTelegram(c.Request.Context(), req.ExternalID, req.LanguageCode, req.Username, req.FirstName)
+	acc, created, err := s.accounts.ProvisionTelegram(c.Request.Context(), req.ExternalID, req.LanguageCode, req.Username, req.FirstName, req.BrowserTZ)
 	if err != nil {
 		s.abortErr(c, err)
 		return
@@ -45,6 +52,47 @@ func (s *Server) handleTelegramAuth(c *gin.Context) {
 		// joined the chat before registering is granted on the spot (no chat_member
 		// event fires on registration).
 		s.publishChatAccessChange(acc.ID)
+		// A promo deep-link may seed this brand-new account's variant preferences (e.g.
+		// English Scrabble alongside the default Erudit). Best-effort: an absent or
+		// malformed payload leaves the account on its defaults, and a write failure must
+		// not block the session mint.
+		if seed := account.SeedVariantsFromStartParam(req.StartParam); len(seed) > 0 {
+			if _, err := s.accounts.SetVariantPreferences(c.Request.Context(), acc.ID, seed); err != nil {
+				s.log.Warn("telegram: seed variant preferences failed",
+					zap.String("account", acc.ID.String()), zap.Error(err))
+			}
+		}
+	}
+	s.mintSession(c, acc)
+}
+
+// vkAuthRequest carries the identity the gateway extracted from verified VK launch
+// params. LanguageCode (vk_language) and DisplayName (read client-side via
+// VKWebAppGetUserInfo, since VK omits the name from the signed params) seed a brand-new
+// account's language and display name; BrowserTZ (the client's detected "±HH:MM" UTC
+// offset) seeds its time zone. All seeds apply on first contact only.
+type vkAuthRequest struct {
+	ExternalID   string `json:"external_id"`
+	LanguageCode string `json:"language_code"`
+	DisplayName  string `json:"display_name"`
+	BrowserTZ    string `json:"browser_tz"`
+}
+
+// handleVKAuth provisions (or finds) the account bound to a VK identity and mints a
+// session for it, seeding a new account's language and display name from the supplied VK
+// fields (first contact only). Unlike Telegram there is no moderated-chat re-evaluation
+// or deep-link variant seed: a fresh VK account has no Telegram chat eligibility and the
+// MVP carries no launch deep link.
+func (s *Server) handleVKAuth(c *gin.Context) {
+	var req vkAuthRequest
+	if err := c.ShouldBindJSON(&req); err != nil || req.ExternalID == "" {
+		abortBadRequest(c, "external_id is required")
+		return
+	}
+	acc, _, err := s.accounts.ProvisionVK(c.Request.Context(), req.ExternalID, req.LanguageCode, req.DisplayName, req.BrowserTZ)
+	if err != nil {
+		s.abortErr(c, err)
+		return
 	}
 	s.mintSession(c, acc)
 }
@@ -97,9 +145,21 @@ func (s *Server) handlePushTarget(c *gin.Context) {
 	})
 }
 
-// handleGuestAuth provisions a fresh ephemeral guest account and mints a session.
+// guestAuthRequest carries the guest bootstrap's optional time-zone seed: BrowserTZ
+// (the client's detected "±HH:MM" UTC offset) is written to the new guest account's
+// time zone, so robot timing is anchored to the player's zone from the first game.
+type guestAuthRequest struct {
+	BrowserTZ string `json:"browser_tz"`
+}
+
+// handleGuestAuth provisions a fresh ephemeral guest account and mints a session,
+// seeding its time zone from the optional detected browser offset.
 func (s *Server) handleGuestAuth(c *gin.Context) {
-	acc, err := s.accounts.ProvisionGuest(c.Request.Context())
+	// The body is optional: an absent or malformed one simply yields no time-zone seed
+	// (the account keeps the UTC default), so a bind error must not fail the bootstrap.
+	var req guestAuthRequest
+	_ = c.ShouldBindJSON(&req)
+	acc, err := s.accounts.ProvisionGuest(c.Request.Context(), req.BrowserTZ)
 	if err != nil {
 		s.abortErr(c, err)
 		return
@@ -107,9 +167,13 @@ func (s *Server) handleGuestAuth(c *gin.Context) {
 	s.mintSession(c, acc)
 }
 
-// emailRequest is an email-login code request.
+// emailRequest is an email-login code request. BrowserTZ (the client's detected
+// "±HH:MM" UTC offset) seeds the time zone of an account provisioned here on first
+// contact (the email account is created at the request step, not at login).
 type emailRequest struct {
 	Email     string `json:"email"`
+	BrowserTZ string `json:"browser_tz"`
+	Language  string `json:"language"`
 }
 
 // handleEmailRequest issues a login confirm-code to the email. It always reports
@@ -121,7 +185,7 @@ func (s *Server) handleEmailRequest(c *gin.Context) {
 		abortBadRequest(c, "email is required")
 		return
 	}
-	if _, err := s.emails.RequestLoginCode(c.Request.Context(), req.Email); err != nil {
+	if _, err := s.emails.RequestLoginCode(c.Request.Context(), req.Email, req.BrowserTZ, req.Language); err != nil {
 		s.abortErr(c, err)
 		return
 	}
@@ -149,6 +213,56 @@ func (s *Server) handleEmailLogin(c *gin.Context) {
 	s.mintSession(c, acc)
 }
 
+// confirmLinkResponse is the outcome of a one-tap deeplink confirmation. For a login,
+// Session carries the freshly minted credential (the deeplink page signs in with it);
+// for a link, Status is "confirmed" or "merge_required" (the app completes the merge).
+type confirmLinkResponse struct {
+	Purpose string           `json:"purpose"`
+	Status  string           `json:"status"`
+	Session *sessionResponse `json:"session,omitempty"`
+}
+
+// handleEmailConfirmLink verifies a one-tap deeplink token. A login mints a session
+// (the deeplink page signs in with it); a link attaches the confirmed email, reporting
+// "merge_required" when the address is owned by another account so the app drives the
+// interactive merge. The token, not a request session, is the authorization — the page
+// need not be signed in.
+func (s *Server) handleEmailConfirmLink(c *gin.Context) {
+	var req tokenRequest
+	if err := c.ShouldBindJSON(&req); err != nil || req.Token == "" {
+		abortBadRequest(c, "token is required")
+		return
+	}
+	res, err := s.emails.ConfirmByToken(c.Request.Context(), req.Token)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	if res.IsLogin() {
+		acc, err := s.accounts.GetByID(c.Request.Context(), res.Account)
+		if err != nil {
+			s.abortErr(c, err)
+			return
+		}
+		token, _, err := s.sessions.Create(c.Request.Context(), acc.ID)
+		if err != nil {
+			s.abortErr(c, err)
+			return
+		}
+		sess := sessionResponseFor(token, acc)
+		c.JSON(http.StatusOK, confirmLinkResponse{Purpose: "login", Status: "confirmed", Session: &sess})
+		return
+	}
+	if res.NeedsMerge {
+		c.JSON(http.StatusOK, confirmLinkResponse{Purpose: "link", Status: "merge_required"})
+		return
+	}
+	// A free link attached the email; nudge the account's in-app session(s) to re-fetch
+	// the profile, so a link confirmed in another browser reflects at once.
+	s.notifier.Publish(notify.ProfileChanged(res.Account))
+	c.JSON(http.StatusOK, confirmLinkResponse{Purpose: "link", Status: "confirmed"})
+}
+
 // tokenRequest carries an opaque session token.
 type tokenRequest struct {
 	Token string `json:"token"`

backend/internal/server/handlers_delete.go

@@ -0,0 +1,131 @@
+package server
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+
+	"scrabble/backend/internal/accountdelete"
+	"scrabble/backend/internal/game"
+)
+
+// Account deletion is legal retention, not erasure (docs/ARCHITECTURE.md §9.1): the account
+// row survives as a tombstone while its credentials are journalled + freed, its live
+// surfaces anonymised, and its own social/ephemeral data dropped. Messages are kept. The
+// step-up is a mailed code for an account with a confirmed email, or a typed phrase for a
+// platform-only account (possession-proof is unattainable there, so the phrase is
+// anti-impulse only).
+
+// deletePhrase is the fixed confirmation phrase a no-email account types to delete.
+// Compared case-insensitively; the client localises only the surrounding instruction.
+const deletePhrase = "DELETE"
+
+// deleteRequestResponse tells the client which step-up the account uses.
+type deleteRequestResponse struct {
+	Method string `json:"method"` // "email" | "phrase"
+}
+
+// handleRequestDelete starts account deletion: it mails a delete code to an account with a
+// confirmed email, or reports the typed-phrase path otherwise.
+func (s *Server) handleRequestDelete(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	ctx := c.Request.Context()
+	hasEmail, err := s.emails.HasEmail(ctx, uid)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	if !hasEmail {
+		c.JSON(http.StatusOK, deleteRequestResponse{Method: "phrase"})
+		return
+	}
+	if err := s.emails.RequestDeleteCode(ctx, uid); err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, deleteRequestResponse{Method: "email"})
+}
+
+// deleteConfirmBody carries the step-up proof: a mailed code (email account) or the typed
+// phrase (platform-only account).
+type deleteConfirmBody struct {
+	Code   string `json:"code"`
+	Phrase string `json:"phrase"`
+}
+
+// handleConfirmDelete verifies the step-up and deletes the account.
+func (s *Server) handleConfirmDelete(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	var req deleteConfirmBody
+	if err := c.ShouldBindJSON(&req); err != nil {
+		abortBadRequest(c, "invalid request body")
+		return
+	}
+	ctx := c.Request.Context()
+	hasEmail, err := s.emails.HasEmail(ctx, uid)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	if hasEmail {
+		if err := s.emails.VerifyDeleteCode(ctx, uid, req.Code); err != nil {
+			s.abortErr(c, err)
+			return
+		}
+	} else if !strings.EqualFold(strings.TrimSpace(req.Phrase), deletePhrase) {
+		abortBadRequest(c, "confirmation phrase does not match")
+		return
+	}
+	if err := s.deleteAccount(ctx, uid); err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, okResponse{OK: true})
+}
+
+// deleteAccount runs the deletion orchestration after the step-up passed: it resigns the
+// account's active games (so opponents are not stranded and robot games end cleanly),
+// drops its all-robot games, tombstones + anonymises the account (journalling and freeing
+// its credentials), and revokes its sessions. The tombstone is the point of no return —
+// its failure aborts; the game cleanup and session revocation around it are best-effort.
+func (s *Server) deleteAccount(ctx context.Context, uid uuid.UUID) error {
+	deleter := accountdelete.NewDeleter(s.db)
+	if s.games != nil {
+		if games, err := s.games.ListForAccount(ctx, uid); err == nil {
+			for _, g := range games {
+				if g.Status != game.StatusActive {
+					continue
+				}
+				if _, err := s.games.Resign(ctx, g.ID, uid); err != nil {
+					s.log.Warn("delete: resign game failed", zap.String("game", g.ID.String()), zap.Error(err))
+				}
+			}
+		} else {
+			s.log.Warn("delete: list games failed", zap.Error(err))
+		}
+	}
+	if _, err := deleter.DropAllRobotGames(ctx, uid); err != nil {
+		s.log.Warn("delete: drop all-robot games failed", zap.Error(err))
+	}
+	if err := deleter.AnonymizeAndTombstone(ctx, uid); err != nil {
+		return err
+	}
+	if s.sessions != nil {
+		if err := s.sessions.RevokeAllForAccount(ctx, uid); err != nil {
+			s.log.Warn("delete: revoke sessions failed", zap.Error(err))
+		}
+	}
+	return nil
+}

backend/internal/server/handlers_dict.go

@@ -0,0 +1,31 @@
+package server
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"scrabble/backend/internal/engine"
+)
+
+// handleDictBytes streams the raw serialized dictionary for a (variant, version)
+// pair so the client can validate and score moves locally — the local move
+// preview — instead of a network round trip per tile arrangement. It is reached
+// only through the gateway's session-gated /dict route (which resolves the
+// X-User-ID this group requires), and served with a long immutable cache lifetime
+// because a published dictionary version never changes. An unknown variant or a
+// version that is not resident is a 404.
+func (s *Server) handleDictBytes(c *gin.Context) {
+	variant, err := engine.ParseVariant(c.Param("variant"))
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "unknown variant"})
+		return
+	}
+	data, err := s.games.DictBytes(variant, c.Param("version"))
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "dictionary not found"})
+		return
+	}
+	c.Header("Cache-Control", "public, max-age=31536000, immutable")
+	c.Data(http.StatusOK, "application/octet-stream", data)
+}

backend/internal/server/handlers_feedback.go

@@ -16,6 +16,12 @@ type feedbackSubmitRequest struct {
 	Attachment     string `json:"attachment"`
 	AttachmentName string `json:"attachment_name"`
 	Channel        string `json:"channel"`
+	// Version is the client's app version (pkg/version / the SPA build), snapshotted so the
+	// operator sees which build a report came from.
+	Version string `json:"version"`
+	// BrowserTZ is the client's detected UTC offset ("±HH:MM") at submit, so the operator can
+	// see the filed time in the sender's local zone even before they save a profile.
+	BrowserTZ string `json:"browser_tz"`
 }
 
 // feedbackReplyDTO is the operator's reply shown back to the player.
@@ -61,7 +67,7 @@ func (s *Server) handleFeedbackSubmit(c *gin.Context) {
 		}
 		attachment = data
 	}
-	if err := s.feedback.Submit(c.Request.Context(), uid, req.Body, attachment, req.AttachmentName, req.Channel, clientIP(c)); err != nil {
+	if err := s.feedback.Submit(c.Request.Context(), uid, req.Body, attachment, req.AttachmentName, req.Channel, req.Version, req.BrowserTZ, clientIP(c)); err != nil {
 		s.abortErr(c, err)
 		return
 	}

backend/internal/server/handlers_link.go

@@ -7,6 +7,7 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/google/uuid"
 
+	"scrabble/backend/internal/account"
 	"scrabble/backend/internal/link"
 )
 
@@ -33,6 +34,12 @@ type linkTelegramBody struct {
 	ExternalID string `json:"external_id"`
 }
 
+// linkVKBody carries a gateway-validated VK identity (the trusted vk user id the
+// gateway resolved from the VK ID code exchange).
+type linkVKBody struct {
+	ExternalID string `json:"external_id"`
+}
+
 // linkResultResponse is the unified result of a confirm or merge step. Status is
 // "linked" (bound to the caller), "merge_required" (the identity belongs to another
 // account — the secondary_* fields summarise it for the irreversible confirmation),
@@ -66,6 +73,89 @@ func (s *Server) handleLinkEmailRequest(c *gin.Context) {
 	c.JSON(http.StatusOK, okResponse{OK: true})
 }
 
+// unlinkBody carries the provider kind to detach.
+type unlinkBody struct {
+	Kind string `json:"kind"`
+}
+
+// handleUnlink detaches a platform identity (telegram or vk) from the caller's
+// account, refusing to remove the last identity (ErrLastIdentity). Email is never
+// unlinked — it is replaced through the change-email flow — so an email kind is
+// rejected. It returns the refreshed profile so the client updates its controls.
+func (s *Server) handleUnlink(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	var req unlinkBody
+	if err := c.ShouldBindJSON(&req); err != nil {
+		abortBadRequest(c, "invalid request body")
+		return
+	}
+	if req.Kind != account.KindTelegram && req.Kind != account.KindVK {
+		abortBadRequest(c, "only telegram or vk can be unlinked")
+		return
+	}
+	ctx := c.Request.Context()
+	if err := s.accounts.RemoveIdentity(ctx, uid, req.Kind); err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	acc, err := s.accounts.GetByID(ctx, uid)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	r := s.profileResponse(ctx, acc)
+	c.JSON(http.StatusOK, linkResultResponse{Status: "unlinked", Profile: &r})
+}
+
+// handleChangeEmailRequest mails a confirm-code to a new address for an authenticated
+// email change. Like the link request it never signals "taken" up front — a conflict is
+// only revealed (non-disclosingly) at confirm.
+func (s *Server) handleChangeEmailRequest(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	var req linkEmailRequestBody
+	if err := c.ShouldBindJSON(&req); err != nil {
+		abortBadRequest(c, "invalid request body")
+		return
+	}
+	if err := s.emails.RequestChangeCode(c.Request.Context(), uid, req.Email); err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, okResponse{OK: true})
+}
+
+// handleChangeEmailConfirm verifies the code and atomically switches the account to the
+// new address, returning the refreshed profile. A new address confirmed by another
+// account is refused (ErrEmailTaken → the non-disclosing message), never merged.
+func (s *Server) handleChangeEmailConfirm(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	var req linkEmailConfirmBody
+	if err := c.ShouldBindJSON(&req); err != nil {
+		abortBadRequest(c, "invalid request body")
+		return
+	}
+	ctx := c.Request.Context()
+	acc, err := s.emails.ConfirmChange(ctx, uid, req.Email, req.Code)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	r := s.profileResponse(ctx, acc)
+	c.JSON(http.StatusOK, linkResultResponse{Status: "changed", Profile: &r})
+}
+
 // handleLinkEmailConfirm verifies the code and binds a free email or reports a
 // required merge.
 func (s *Server) handleLinkEmailConfirm(c *gin.Context) {
@@ -149,6 +239,48 @@ func (s *Server) handleLinkTelegramMerge(c *gin.Context) {
 	c.JSON(http.StatusOK, s.mergeResultResponse(c, res))
 }
 
+// handleLinkVK attaches a gateway-validated VK identity to the caller or reports a
+// required merge.
+func (s *Server) handleLinkVK(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	var req linkVKBody
+	if err := c.ShouldBindJSON(&req); err != nil || req.ExternalID == "" {
+		abortBadRequest(c, "missing external_id")
+		return
+	}
+	res, err := s.links.ConfirmVK(c.Request.Context(), uid, req.ExternalID)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, s.confirmResultResponse(c, uid, res))
+}
+
+// handleLinkVKMerge merges the account owning a gateway-validated VK identity into
+// the caller's.
+func (s *Server) handleLinkVKMerge(c *gin.Context) {
+	uid, ok := userID(c)
+	if !ok {
+		abortBadRequest(c, "missing identity")
+		return
+	}
+	var req linkVKBody
+	if err := c.ShouldBindJSON(&req); err != nil || req.ExternalID == "" {
+		abortBadRequest(c, "missing external_id")
+		return
+	}
+	res, err := s.links.MergeVK(c.Request.Context(), uid, req.ExternalID)
+	if err != nil {
+		s.abortErr(c, err)
+		return
+	}
+	c.JSON(http.StatusOK, s.mergeResultResponse(c, res))
+}
+
 // confirmResultResponse renders a confirm step: a merge preview (secondary summary)
 // or a completed link (the active account's refreshed profile).
 func (s *Server) confirmResultResponse(c *gin.Context, activeID uuid.UUID, res link.ConfirmResult) linkResultResponse {