[Feature] 用户希望批量上传文件大小限制会告诉用户具体是哪个文件有问题

### MaxKB Version

v2

### Please describe your needs or suggestions for improvements

反馈体验并不好，用户不知道具体哪个文件不符合校验

<img width="265" height="1009" alt="Image" src="https://github.com/user-attachments/assets/cc30ea4f-798c-4876-98b3-d8a9801b1a50" />

### Please describe the solution you suggest

_No response_

### Additional Information

_No response_