- Add a 10-second countdown timer between ball draws with a dedicated UI overlay
- Implement visual flash effect on opponent panels when their cards match the called number
- Play happy emotion animation on opponent portraits during matches
- Replace CASINO_WIN/LOSE sounds with CASINO_BLACKJACK for win/loss events
- Fix fullscreen toggle to properly handle exitFullscreen and requestFullscreen
- Add new video assets for opponent emotions (happy, idle, upset)
