[Improvement] When uploading the same document multiple times, the knowledge base summary will classify them into multiple categories.

### Improvement Description

<img width="1186" height="432" alt="Image" src="https://github.com/user-attachments/assets/48240fd5-d061-416a-a021-0f5e856a95c5" />

<img width="1873" height="678" alt="Image" src="https://github.com/user-attachments/assets/a28ba8ca-1ee2-4dbb-971a-30ec80b7154f" />