build: add Docker and CI/CD pipeline for web deployment

- Add multi-stage Dockerfile (Flutter build → nginx:alpine)
- Add nginx.conf with SPA routing, gzip, and caching
- Add Gitea workflow for release-triggered builds
- Document release procedure in AGENTS.md

Deploys to port 8092, auto-updates via Watchtower.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -0,0 +1,34 @@
+name: Build and Push
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Login to Gitea Registry
+        uses: docker/login-action@v3
+        with:
+          registry: git.schweitz.internal
+          username: ${{ secrets.REGISTRY_USER }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: |
+            git.schweitz.internal/jpmschweitzer/tatlock-ui:latest
+            git.schweitz.internal/jpmschweitzer/tatlock-ui:${{ github.ref_name }}
+
+      - name: Trigger Watchtower update
+        if: success()
+        run: |
+          curl -sf -H "Authorization: Bearer ${{ secrets.WATCHTOWER_TOKEN }}" \
+            http://watchtower:8080/v1/update