feat(deploy): serve SPA from server, Dockerfile, compose, deploy docs

- Add serveStatic middleware to server/src/app.ts to serve web/dist
- Include SPA fallback route for client-side routing deep links
- Create Dockerfile with multi-stage build (Node deps + build, slim runtime)
- Add docker-compose.yml for single-command deployment
- Add docs/deploy.md with deployment instructions and Caddy reverse proxy example
- Add bun run build:web step to CI pipeline after typecheck

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -14,4 +14,5 @@ jobs:
           git init -q . && git fetch -q --depth 1 "https://git.rehbock.xyz/${{ github.repository }}.git" "${{ github.sha }}" && git checkout -q FETCH_HEAD
       - run: bun install --frozen-lockfile
       - run: bun run typecheck
+      - run: bun run build:web
       - run: bun test server