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_task6.py

@@ -29,7 +29,6 @@ backend_dir = os.path.dirname(os.path.abspath(__file__))
 if backend_dir not in sys.path:
     sys.path.insert(0, backend_dir)
 
-
 class TestDeveloperEcosystem:
     """开发者生态系统测试类"""
 
@@ -688,12 +687,10 @@ console.log('Upload complete:', result.id);
 
         print("=" * 60)
 
-
 def main():
     """主函数"""
     test = TestDeveloperEcosystem()
     test.run_all_tests()
 
-
 if __name__ == "__main__":
     main()