fix: auto-fix code issues (cron)

- 修复重复导入/字段
- 修复异常处理 (BaseException -> 具体异常类型)
- 修复PEP8格式问题
- 添加类型注解
- 修复tingwu_client.py缩进错误

backend/tingwu_client.py

@@ -34,24 +34,6 @@ class TingwuClient:
 
     def create_task(self, audio_url: str, language: str = "zh") -> str:
         """创建听悟任务"""
-        endpoint = f"{self.endpoint}/openapi/tingwu/v2/tasks"
-
-        payload = {
-            "Input": {
-                "Source": "OSS",
-                "FileUrl": audio_url
-            },
-            "Parameters": {
-                "Transcription": {
-                    "DiarizationEnabled": True,
-                    "SentenceMaxLength": 20
-                }
-            }
-        }
-
-        # 使用阿里云 SDK 方式调用 (endpoint 和 payload 供后续扩展使用)
-        _ = endpoint
-        _ = payload
         try:
             from alibabacloud_tingwu20230930 import models as tingwu_models
             from alibabacloud_tingwu20230930.client import Client as TingwuSDKClient