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/test_phase8_task5.py

@@ -13,14 +13,20 @@ InsightFlow Phase 8 Task 5 - 运营与增长工具测试脚本
     python test_phase8_task5.py
 """
 
-from growth_manager import (
-    GrowthManager, EventType, ExperimentStatus, TrafficAllocationType, EmailTemplateType, WorkflowTriggerType
-)
 import asyncio
-import sys
 import os
+import sys
 from datetime import datetime, timedelta
 
+from growth_manager import (
+    EmailTemplateType,
+    EventType,
+    ExperimentStatus,
+    GrowthManager,
+    TrafficAllocationType,
+    WorkflowTriggerType,
+)
+
 # 添加 backend 目录到路径
 backend_dir = os.path.dirname(os.path.abspath(__file__))
 if backend_dir not in sys.path: