Initial commit: Pole Dance Championships App

Full-stack mobile app for pole dance championship management.

Backend: FastAPI + SQLAlchemy 2 (async) + SQLite (dev) / PostgreSQL (prod)
- JWT auth with refresh token rotation
- Championship CRUD with Instagram Graph API sync (APScheduler)
- Registration flow with status management
- Participant list publish with Expo push notifications
- Alembic migrations, pytest test suite

Mobile: React Native + Expo (TypeScript)
- Auth gate: pending approval screen for new members
- Championships list & detail screens
- Registration form with status tracking
- React Query + Zustand + React Navigation v6

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/database.py

@@ -0,0 +1,47 @@
+from typing import AsyncGenerator
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase
+
+from app.config import settings
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def _make_engine():
+    return create_async_engine(settings.database_url, echo=False)
+
+
+def _make_session_factory(engine):
+    return async_sessionmaker(engine, expire_on_commit=False)
+
+
+# Lazily initialised on first use so tests can patch settings before import
+_engine = None
+_session_factory = None
+
+
+def get_engine():
+    global _engine
+    if _engine is None:
+        _engine = _make_engine()
+    return _engine
+
+
+def get_session_factory():
+    global _session_factory
+    if _session_factory is None:
+        _session_factory = _make_session_factory(get_engine())
+    return _session_factory
+
+
+# Alias kept for Alembic and bot usage
+AsyncSessionLocal = None  # populated on first call to get_session_factory()
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    factory = get_session_factory()
+    async with factory() as session:
+        yield session