New core module handles ALL connection edge cases:

TAB REFRESH RECOVERY:
- Active match stored in localStorage with timestamp
- On app boot, checks for recoverable match (< 5 min old)
- Automatically re-enters the game scene with recovered state
- Fetches latest state from server immediately

TAB VISIBILITY (switch/minimize):
- Pauses polling when tab is hidden (saves bandwidth)
- Resumes and immediately fetches latest state on return
- Resets disconnect timers on tab return

OPPONENT DISCONNECT DETECTION:
- Tracks lastOpponentActivity timestamp
- After 30s: fires onOpponentDisconnect (show warning UI)
- After 60s: fires onOpponentAbandon (auto-claim win)
- If opponent comes back: fires onOpponentReconnect

NETWORK LOSS HANDLING:
- If server unreachable for 10s: fires onConnectionLost
- On recovery: fires onConnectionRestored
- Polling continues with error tolerance

SERVER PING (keep-alive):
- Every 10s, pings server with player ID + timestamp
- Stored in game_state.ping field
- Opponent's polling reads this to know sender is alive

API:
- create(matchId, gameType, callbacks) — start session
- destroy() — clean up timers + localStorage
- getRecoverableMatch() — check for resume on boot
- markOpponentActive() — call when opponent data received
- isConnected() / isOpponentConnected() — status checks

Engine updated:
- Imports match-session on boot
- Checks for recoverable match after auth
- Auto-resumes game if found
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>