fix: auto-fix code issues (cron)

- 修复重复导入/字段
- 修复异常处理
- 修复PEP8格式问题
- 添加类型注解

backend/enterprise_manager.py

@@ -329,7 +329,7 @@ class EnterpriseManager:
         conn.row_factory = sqlite3.Row
         return conn
 
-    def _init_db(self):
+    def _init_db(self) -> None:
         """初始化数据库表"""
         conn = self._get_connection()
         try:
@@ -1190,7 +1190,7 @@ class EnterpriseManager:
         # GET {scim_base_url}/Users
         return []
 
-    def _upsert_scim_user(self, conn: sqlite3.Connection, tenant_id: str, user_data: dict[str, Any]):
+    def _upsert_scim_user(self, conn: sqlite3.Connection, tenant_id: str, user_data: dict[str, Any]) -> None:
         """插入或更新 SCIM 用户"""
         cursor = conn.cursor()