feat: Sprint 1 foundation - FastAPI scaffold, DB schema, auth, seed data, mock WhatsApp, Docker

app/core/database.py

@@ -0,0 +1,33 @@
+"""Database engine, session factory, and Base."""
+
+from __future__ import annotations
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase
+
+from app.core.config import settings
+
+engine = create_async_engine(settings.DATABASE_URL, echo=settings.DEBUG)
+
+async_session_factory = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+async def get_db() -> AsyncSession:  # type: ignore[misc]
+    """FastAPI dependency that yields an async DB session."""
+    async with async_session_factory() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()