fix: Knowledge Base Improvements (#12023)

* fix: improve knowledge base UI consistency and pagination handling

- Change quote style from double to single quotes throughout knowledge base components
- Update "Hide Sources" button label to "Hide Configuration" for clarity
- Restructure SourceChunksPage layout to use xl:container for consistent spacing
- Add controlled page input state with validation on blur and Enter key
- Synchronize page input field with pagination controls to prevent state drift
- Reset page input to "1" when changing page

* refactor: extract page input commit logic into reusable function

Extract page input validation and commit logic from handlePageInputBlur and handlePageInputKeyDown into a shared commitPageInput function to eliminate code duplication.