style: apply black formatting to pass CI validation (#126)

apps/api/app/core/database.py

@@ -2,6 +2,7 @@
 
 统一使用 app.config 中的数据库配置，移除重复的 DatabaseSettings。
 """
+
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker, Session
 from contextlib import contextmanager
@@ -9,7 +10,6 @@ from typing import Generator
 
 from app.config import settings
 
-
 engine = create_engine(
     settings.database_url,
     pool_size=settings.DATABASE_POOL_SIZE,
@@ -33,7 +33,7 @@ def get_db() -> Generator[Session, None, None]:
 @contextmanager
 def get_db_context() -> Generator[Session, None, None]:
     """Context manager for database sessions.
-    
+
     Usage:
         with get_db_context() as db:
             db.query(Model).all()