code-review-fix task 14.2: remove dead get_db_session function from db.py

services/ml/app/db.py

@@ -87,18 +87,3 @@ def get_db() -> Generator[Session, None, None]:
         yield db
     finally:
         db.close()
-
-
-def get_db_session() -> Session:
-    """
-    Get a database session (for dependency injection).
-
-    Usage with FastAPI:
-        @app.get("/")
-        def endpoint(db: Session = Depends(get_db_session)):
-            # Use db here
-
-    Returns:
-        Database session (caller must close it)
-    """
-    return SessionLocal()