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 (E302, E305, E501)
- 修复行长度超过100字符的问题
- 修复F821未定义名称错误

backend/workflow_manager.py

@@ -38,6 +38,7 @@ DEFAULT_RETRY_DELAY = 5  # 默认重试延迟(秒)
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
+
 class WorkflowStatus(Enum):
     """工作流状态"""
 
@@ -46,6 +47,7 @@ class WorkflowStatus(Enum):
     ERROR = "error"
     COMPLETED = "completed"
 
+
 class WorkflowType(Enum):
     """工作流类型"""
 
@@ -55,6 +57,7 @@ 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"""
 
@@ -63,6 +66,7 @@ class WebhookType(Enum):
     SLACK = "slack"
     CUSTOM = "custom"
 
+
 class TaskStatus(Enum):
     """任务执行状态"""
 
@@ -72,6 +76,7 @@ class TaskStatus(Enum):
     FAILED = "failed"
     CANCELLED = "cancelled"
 
+
 @dataclass
 class WorkflowTask:
     """工作流任务定义"""
@@ -95,6 +100,7 @@ class WorkflowTask:
         if not self.updated_at:
             self.updated_at = self.created_at
 
+
 @dataclass
 class WebhookConfig:
     """Webhook 配置"""
@@ -119,6 +125,7 @@ class WebhookConfig:
         if not self.updated_at:
             self.updated_at = self.created_at
 
+
 @dataclass
 class Workflow:
     """工作流定义"""
@@ -148,6 +155,7 @@ class Workflow:
         if not self.updated_at:
             self.updated_at = self.created_at
 
+
 @dataclass
 class WorkflowLog:
     """工作流执行日志"""
@@ -168,6 +176,7 @@ 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"""
 
@@ -323,6 +332,7 @@ 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"""
 
@@ -1493,9 +1503,11 @@ class WorkflowManager:
             ]
         }
 
+
 # Singleton instance
 _workflow_manager = None
 
+
 def get_workflow_manager(db_manager=None) -> WorkflowManager:
     """获取 WorkflowManager 单例"""
     global _workflow_manager