style: format all Python files with Black

Apply Black formatter to the entire codebase for consistent code style.

Co-Authored-By: Claude (glm-5) <noreply@anthropic.com>

db/sqlserver_connection.py

@@ -38,7 +38,7 @@ class SQLServerConnection(BaseDatabaseConnection):
             return self.connection
 
         # 构建连接字符串
-        driver = self.config.get('driver', 'ODBC Driver 18 for SQL Server')
+        driver = self.config.get("driver", "ODBC Driver 18 for SQL Server")
         conn_str = (
             f"DRIVER={{{driver}}};"
             f"SERVER={self.config['server']};"