DOC: Fix broken docs links

### What's wrong with the existing documentation

docs/index.md links to two frontend pages that don’t exist:
./frontend/ui-components
./frontend/gallery-view
Under Frontend, the site only has State Management and Screenshots (see mkdocs.yml). So those two links are broken.

### Add ScreenShots

_No response_

### Record

- [x] I agree to follow this project's Code of Conduct
- [x] I want to work on this issue