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/workflow_manager.py

@@ -33,7 +33,6 @@ from apscheduler.triggers.interval import IntervalTrigger
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
-
 class WorkflowStatus(Enum):
     """工作流状态"""
 
@@ -42,7 +41,6 @@ class WorkflowStatus(Enum):
     ERROR = "error"
     COMPLETED = "completed"
 
-
 class WorkflowType(Enum):
     """工作流类型"""
 
@@ -52,7 +50,6 @@ class WorkflowType(Enum):
     SCHEDULED_REPORT = "scheduled_report"  # 定时报告
     CUSTOM = "custom"  # 自定义工作流
 
-
 class WebhookType(Enum):
     """Webhook 类型"""
 
@@ -61,7 +58,6 @@ class WebhookType(Enum):
     SLACK = "slack"
     CUSTOM = "custom"
 
-
 class TaskStatus(Enum):
     """任务执行状态"""
 
@@ -71,7 +67,6 @@ class TaskStatus(Enum):
     FAILED = "failed"
     CANCELLED = "cancelled"
 
-
 @dataclass
 class WorkflowTask:
     """工作流任务定义"""
@@ -95,7 +90,6 @@ class WorkflowTask:
         if not self.updated_at:
             self.updated_at = self.created_at
 
-
 @dataclass
 class WebhookConfig:
     """Webhook 配置"""
@@ -120,7 +114,6 @@ class WebhookConfig:
         if not self.updated_at:
             self.updated_at = self.created_at
 
-
 @dataclass
 class Workflow:
     """工作流定义"""
@@ -150,7 +143,6 @@ class Workflow:
         if not self.updated_at:
             self.updated_at = self.created_at
 
-
 @dataclass
 class WorkflowLog:
     """工作流执行日志"""
@@ -171,7 +163,6 @@ class WorkflowLog:
         if not self.created_at:
             self.created_at = datetime.now().isoformat()
 
-
 class WebhookNotifier:
     """Webhook 通知器 - 支持飞书、钉钉、Slack"""
 
@@ -327,7 +318,6 @@ class WebhookNotifier:
         """关闭 HTTP 客户端"""
         await self.http_client.aclose()
 
-
 class WorkflowManager:
     """工作流管理器 - 核心管理类"""
 
@@ -1498,11 +1488,9 @@ class WorkflowManager:
             ]
         }
 
-
 # Singleton instance
 _workflow_manager = None
 
-
 def get_workflow_manager(db_manager=None) -> WorkflowManager:
     """获取 WorkflowManager 单例"""
     global _workflow_manager