- Add Skeleton base component with variants: text, rectangular, circular
- Add SkeletonText for multi-line text placeholders
- Add SkeletonCard for card-shaped loading states
- Add SkeletonTable for table loading with configurable rows/columns
- Add SkeletonAvatar for avatar placeholders (sm/md/lg/xl)
- Add SkeletonButton for button placeholders
- Add shimmer animation to Tailwind config
- Add comprehensive tests (21 tests passing)
- Export all components from common/index.ts
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>