Add pytest fixtures (engine, db_session, client) with session-scoped
event loop to avoid asyncpg loop mismatch errors. Smoke tests verify
all three main API endpoints return empty results on a clean DB.
Test DB provided by docker-compose.test.yml on port 5433.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Game Data Cleanup → critical, Tests → high, pre-commit hooks → high,
boss battles → low, remaining epics → deferred.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
