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
- 修复重复函数定义 (health_check, create_webhook_endpoint, etc)
- 修复未定义名称 (SearchOperator, TenantTier, Query, Body, logger)
- 修复 workflow_manager.py 的类定义重复问题
- 添加缺失的导入

backend/init_db.py

@@ -11,7 +11,7 @@ print(f"Database path: {db_path}")
 print(f"Schema path: {schema_path}")
 
 # Read schema
-with open(schema_path, 'r') as f:
+with open(schema_path, "r") as f:
     schema = f.read()
 
 # Execute schema
@@ -19,7 +19,7 @@ conn = sqlite3.connect(db_path)
 cursor = conn.cursor()
 
 # Split schema by semicolons and execute each statement
-statements = schema.split(';')
+statements = schema.split(";")
 success_count = 0
 error_count = 0