ci: split workflows for linear development flow

Reshapes .gitea/workflows/ around the new main ← development ←
feature/* branching model:

- go-unit.yaml — Go unit tests, runs on push/PR matching Go paths
- ui-test.yaml — narrowed to Vitest + Playwright only (Go tests now
  live in go-unit.yaml)
- integration.yaml — testcontainers suite, fires on PR to
  development/main and on push to development
- dev-deploy.yaml — builds the stack and (re)deploys tools/dev-deploy/
  on every merge into development
- prod-build.yaml — builds prod images on push to main and uploads
  docker save bundles as artifacts (30-day retention)
- deploy-prod.yaml — workflow_dispatch placeholder for the future
  SSH-based rollout

ui-release.yaml is removed; its v* tag trigger is superseded by
prod-build.yaml plus the manual deploy-prod entry point.

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

.gitea/workflows/integration.yaml

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