Build a memory card matching game:
- Grid of face-down cards (use emoji or simple icons)
- Flip two cards at a time - match = stay revealed
- Difficulty: Easy (4x3), Medium (4x4), Hard (6x4)
- Move counter and timer
- Win screen with stats and time
- Themes: animals, food, flags, numbers
- Smooth flip animation
- Best score tracking (localStorage)
- Mobile-friendly touch support
Put in ~/data/public/