feat: add Chinese LLM providers support with auto-fill API Base URL

- Add support for DeepSeek, Qwen (Alibaba), Kimi (Moonshot), and GLM (Zhipu)
- Implement auto-fill API Base URL when selecting Chinese LLM providers
- Add smart validation and warnings for missing API endpoints
- Fix session state management in task logging service
- Add comprehensive Chinese setup documentation
- Add database migration for new LLM provider enums

Closes #383

surfsense_backend/app/services/task_logging_service.py

@@ -73,6 +73,16 @@ class TaskLoggingService:
         Returns:
             Log: The updated log entry
         """
+        # Ensure session is in a valid state / 确保 session 处于有效状态
+        if not self.session.is_active:
+            await self.session.rollback()
+        
+        # Refresh log_entry to avoid expired state / 刷新 log_entry 避免过期状态
+        try:
+            await self.session.refresh(log_entry)
+        except Exception:
+            pass
+        
         # Update the existing log entry
         log_entry.status = LogStatus.SUCCESS
         log_entry.message = message
@@ -114,6 +124,17 @@ class TaskLoggingService:
         Returns:
             Log: The updated log entry
         """
+        # Ensure session is in a valid state / 确保 session 处于有效状态
+        if not self.session.is_active:
+            await self.session.rollback()
+        
+        # Refresh log_entry to avoid expired state / 刷新 log_entry 避免过期状态
+        try:
+            await self.session.refresh(log_entry)
+        except Exception:
+            # If refresh fails, the object might be detached / 如果刷新失败，对象可能已分离
+            pass
+        
         # Update the existing log entry
         log_entry.status = LogStatus.FAILED
         log_entry.level = LogLevel.ERROR
@@ -161,6 +182,16 @@ class TaskLoggingService:
         Returns:
             Log: The updated log entry
         """
+        # Ensure session is in a valid state / 确保 session 处于有效状态
+        if not self.session.is_active:
+            await self.session.rollback()
+        
+        # Refresh log_entry to avoid expired state / 刷新 log_entry 避免过期状态
+        try:
+            await self.session.refresh(log_entry)
+        except Exception:
+            pass
+        
         log_entry.message = progress_message
 
         if progress_metadata: