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

@@ -32,7 +32,6 @@ backend_dir = os.path.dirname(os.path.abspath(__file__))
 if backend_dir not in sys.path:
     sys.path.insert(0, backend_dir)
 
-
 class TestGrowthManager:
     """测试 Growth Manager 功能"""
 
@@ -735,12 +734,10 @@ class TestGrowthManager:
         print("✨ 测试完成!")
         print("=" * 60)
 
-
 async def main():
     """主函数"""
     tester = TestGrowthManager()
     await tester.run_all_tests()
 
-
 if __name__ == "__main__":
     asyncio.run(main())