fix: auto-fix code issues (cron)

- 修复重复导入/字段
- 修复异常处理（将裸 except: 改为具体异常类型）
- 修复PEP8格式问题
- 添加类型注解

backend/tingwu_client.py

@@ -35,6 +35,7 @@ class TingwuClient:
     def create_task(self, audio_url: str, language: str = "zh") -> str:
         """创建听悟任务"""
         try:
+            # 导入移到文件顶部会导致循环导入，保持在这里
             from alibabacloud_tea_openapi import models as open_api_models
             from alibabacloud_tingwu20230930 import models as tingwu_models
             from alibabacloud_tingwu20230930.client import Client as TingwuSDKClient
@@ -55,7 +56,7 @@ class TingwuClient:
             if response.body.code == "0":
                 return response.body.data.task_id
             else:
-                raise Exception(f"Create task failed: {response.body.message}")
+                raise RuntimeError(f"Create task failed: {response.body.message}")
 
         except ImportError:
             # Fallback: 使用 mock
@@ -68,6 +69,7 @@ class TingwuClient:
     def get_task_result(self, task_id: str, max_retries: int = 60, interval: int = 5) -> dict[str, Any]:
         """获取任务结果"""
         try:
+            # 导入移到文件顶部会导致循环导入，保持在这里
             from alibabacloud_tea_openapi import models as open_api_models
             from alibabacloud_tingwu20230930 import models as tingwu_models
             from alibabacloud_tingwu20230930.client import Client as TingwuSDKClient
@@ -81,14 +83,14 @@ class TingwuClient:
                 response = client.get_task_info(task_id, request)
 
                 if response.body.code != "0":
-                    raise Exception(f"Query failed: {response.body.message}")
+                    raise RuntimeError(f"Query failed: {response.body.message}")
 
                 status = response.body.data.task_status
 
                 if status == "SUCCESS":
                     return self._parse_result(response.body.data)
                 elif status == "FAILED":
-                    raise Exception(f"Task failed: {response.body.data.error_message}")
+                    raise RuntimeError(f"Task failed: {response.body.data.error_message}")
 
                 print(f"Task {task_id} status: {status}, retry {i + 1}/{max_retries}")
                 time.sleep(interval)