feat: highlight duplicate samples within project

Commit notes

- Add contentHash to library API response for duplicate detection - Add duplicate detection state and methods to LibraryState - Add visual highlighting in LibrarySampleGrid: - Colored left border for duplicate sample rows - Duplicate icon indicator in sample row - Header badge showing duplicate set count with toggle - Different duplicate groups use distinct colors for easy identification - Users can toggle duplicate highlighting on/off

Co-authored-by: armin.naimi <[email redacted]>