[Feature] The knowledge base is not repeated by user

### MaxKB Version

2.3.1

### Please describe your needs or suggestions for improvements

<img width="1091" height="831" alt="Image" src="https://github.com/user-attachments/assets/7def6f64-9092-498b-ba14-8f565526c244" />

创建知识库时不同的账号可以创建相同名称的知识库

### Please describe the solution you suggest

_No response_

### Additional Information

_No response_