[Bug]:麻烦适配一下 deepseek API

### Prerequisites|前提条件

- [x] I have checked the [troubleshooting](https://github.com/Anxcye/anx-reader/blob/develop/docs/troubleshooting.md)|我已经查看过[故障排除](https://github.com/Anxcye/anx-reader/blob/develop/docs/troubleshooting.md)
- [x] I have searched for similar issues and did not find any|我已经搜索过没有相同的问题

### Describe the bug|描述问题

Error: BadRequestException: The reasoning_content in the thinking mode must be passed back to the API。

### To reproduce|重现步骤

1. Go to '...' | 前往...
2. Click on '...' | 点击...
3. Scroll down to '...' | 向下滚动到...
4. See error | 看到错误

### Expected behavior|预期行为

出现 reasoning_content 为空字符串，必须原样传回去. 即也在 context 中保留这个值为空字符串的字段. 不能是空对象, 也不能丢掉.

### Screenshots|截图

_No response_

### Platform (please complete the following information)|平台（请填写以下信息）

- Platform: | 平台：Windows

### Additional context|其他信息

_No response_