Phase 5: Real-time multiplayer with matchmaking queue, live clock sync,
and Supabase Realtime for move broadcasting between players.

Phase 7: Friends system with requests/accept/block, notifications with
Realtime subscription, and online presence heartbeat.

Phase 8: Tournaments list with registration and status filters,
leaderboard with time control/period filters and top-3 podium.

Phase 9: Cosmetics shop with rarity system, purchase flow,
daily reward with streak multiplier.

Phase 10: Edit profile modal, recent games on home/profile,
improved settings/404/toast system.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>