- friends.js: invite dialog now shows all 4 games in a 2x2 grid
- friends.php: create/check/accept/decline backgammon invites
- lobby.js: route to backgammon-game scene, show correct icon/label/color
- Time options hidden for non-chess games
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>