add auto migrations

backend/src/app/infra/database.py

@@ -51,6 +51,11 @@ async def get_db() -> AsyncGenerator[AsyncSession, None]:
 
 
 async def init_db() -> None:
-    """Initialize database tables."""
+    """
+    Initialize database tables using create_all().
+
+    WARNING: Only for testing! In production/dev, use Alembic migrations.
+    Using both create_all() and Alembic creates inconsistent state.
+    """
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.create_all)

backend/src/app/main.py

@@ -7,7 +7,6 @@ from fastapi.middleware.cors import CORSMiddleware
 
 from app.api.v1 import assets, auth, batch, folders, shares, uploads
 from app.infra.config import get_settings
-from app.infra.database import init_db
 
 settings = get_settings()
 
@@ -15,8 +14,7 @@ settings = get_settings()
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Application lifespan handler."""
-    # Startup
-    await init_db()
+    # Startup - schema managed by Alembic migrations in Dockerfile
     yield
     # Shutdown
     pass