fix: auto-fix code issues (cron)

- 修复隐式 Optional 类型注解 (RUF013)
- 修复不必要的赋值后返回 (RET504)
- 优化列表推导式 (PERF401)
- 修复未使用的参数 (ARG002)
- 清理重复导入
- 优化异常处理

backend/tingwu_client.py

@@ -19,7 +19,11 @@ class TingwuClient:
             raise ValueError("ALI_ACCESS_KEY and ALI_SECRET_KEY required")
 
     def _sign_request(
-        self, method: str, uri: str, query: str = "", body: str = "",
+        self,
+        method: str,
+        uri: str,
+        query: str = "",
+        body: str = "",
     ) -> dict[str, str]:
         """阿里云签名 V3"""
         timestamp = datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%SZ")
@@ -43,7 +47,8 @@ class TingwuClient:
             from alibabacloud_tingwu20230930.client import Client as TingwuSDKClient
 
             config = open_api_models.Config(
-                access_key_id=self.access_key, access_key_secret=self.secret_key,
+                access_key_id=self.access_key,
+                access_key_secret=self.secret_key,
             )
             config.endpoint = "tingwu.cn-beijing.aliyuncs.com"
             client = TingwuSDKClient(config)
@@ -53,7 +58,8 @@ class TingwuClient:
                 input=tingwu_models.Input(source="OSS", file_url=audio_url),
                 parameters=tingwu_models.Parameters(
                     transcription=tingwu_models.Transcription(
-                        diarization_enabled=True, sentence_max_length=20,
+                        diarization_enabled=True,
+                        sentence_max_length=20,
                     ),
                 ),
             )
@@ -73,7 +79,10 @@ class TingwuClient:
             return f"mock_task_{int(time.time())}"
 
     def get_task_result(
-        self, task_id: str, max_retries: int = 60, interval: int = 5,
+        self,
+        task_id: str,
+        max_retries: int = 60,
+        interval: int = 5,
     ) -> dict[str, Any]:
         """获取任务结果"""
         try:
@@ -83,7 +92,8 @@ class TingwuClient:
             from alibabacloud_tingwu20230930.client import Client as TingwuSDKClient
 
             config = open_api_models.Config(
-                access_key_id=self.access_key, access_key_secret=self.secret_key,
+                access_key_id=self.access_key,
+                access_key_secret=self.secret_key,
             )
             config.endpoint = "tingwu.cn-beijing.aliyuncs.com"
             client = TingwuSDKClient(config)