- Created useIsRateLimited() hook to check rate limit state
- Updated CommentSection submit button to disable when rate limited
- Updated LikeButton to disable when rate limited
- Updated PlaylistForm submit button to disable when rate limited
- Updated ChatInput send button to disable when rate limited
- Updated UploadModal upload button to disable when rate limited
- All buttons check isLimited from rate limit store
- Hook uses Zustand selector for efficient re-renders
- Pattern established for future mutation buttons
- Action 5.4.1.4 complete
- Deleted apps/web/src/utils/optimisticStoreUpdates.ts (unused file)
- File was unused - no imports found in codebase
- Mutations already use React Query's onMutate pattern
- No TypeScript errors after deletion
- Actions 4.4.1.2 and 4.4.1.3 complete
