Initial scopone scientifico backend

Multiplayer scopone scientifico backend on the kaya framework:

- OIDC login (kaya-oidc), session-backed WebSocket auth
- Pure rules engine (forced captures, scopa, primiera scoring) with
  full-match simulation tests
- Live game state in Redis (JSON + TTL, join codes, per-game locks,
  pub/sub state push); in-memory fallback for tests
- WebSocket /ws/games/{id} for real-time play; REST lobby endpoints
  (create/join/snapshot) with hidden-hand views
- Finished matches persisted to Postgres (Tortoise + aerich) for match
  history and leaderboard endpoints
- Docker Compose stack: postgres, redis, mock-oauth2-server, db-migrate, app
- 45 tests passing; mypy clean

.dockerignore

@@ -0,0 +1,21 @@
+# Keep the build context lean: exclude the local venv, caches, tests,
+# and anything not needed to build the scopa wheel.
+.git/
+.gitignore
+.env
+.env.example
+.venv/
+__pycache__/
+*.pyc
+*.pyo
+*.egg-info/
+.mypy_cache/
+.pytest_cache/
+dist/
+build/
+conf/
+tests/
+Dockerfile
+.dockerignore
+opencode.json
+docker-compose.yml