- Created ID normalization utility (idNormalization.ts) with:
* normalizeId: Convert IDs to strings (handles number/string/null)
* normalizeObjectIds: Recursively normalize IDs in objects
* normalizeArrayIds: Normalize IDs in arrays of objects
* Type guards for ID validation
- Updated stores/chat.ts to use normalization instead of manual String() conversions
- Fixed type definitions:
* PlaylistAnalytics: playlistId number -> string
* ImportPlaylistButton: playlistId number -> string
* ExportPlaylistButton: playlistId number -> string
* usePlaylistNotifications: lastNotificationId number -> string
- Removed unnecessary String() conversions in comparisons
- Comprehensive test suite (20 tests, all passing)
- Ensures all IDs are consistently strings (UUIDs) throughout the app
