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

tests/__init__.py

@@ -0,0 +1,17 @@
+"""Test package init.
+
+Sets environment overrides BEFORE any test module imports
+:mod:`scopa.app` (which evaluates :data:`scopa.config.settings`
+at import time). Works under both ``python -m unittest discover`` and
+``pytest``; conftest.py mirrors this for pytest-only collection.
+"""
+from __future__ import annotations
+
+import os
+
+os.environ.setdefault("DATABASE_URL", "sqlite://:memory:")
+os.environ.setdefault("OIDC_ISSUER", "http://localhost:8180/scopa")
+os.environ.setdefault("OIDC_CLIENT_ID", "scopa")
+os.environ.setdefault("OIDC_REDIRECT_URI", "http://localhost:8080/auth/callback")
+# Unset REDIS_URL: sessions and live games use the in-memory fallbacks.
+os.environ.pop("REDIS_URL", None)