f1dbcd0f86
Adds the server side of scaling meetings past the ~5-peer mesh: - config.js: LIVEKIT_URL/API_KEY/API_SECRET + LIVEKIT_ENABLED flag. All optional; when unset the app keeps the built-in P2P mesh (fully additive, like push). - routes.js: GET /api/meetings/config (tells the client sfu on/off + wss url) and POST /api/meetings/token (mints a per-user, per-room LiveKit join token — hand-rolled HS256 JWT like the FCM/APNs tokens, no new dependency; secret stays server-side). - docker-compose.yml: optional livekit service (single-node, no Redis), keys injected via LIVEKIT_KEYS from the same .env; media over published UDP 50000-50100 + TCP 7881, signaling proxied by NPM. - livekit.yaml + .env.example documented. Client (mesh->LiveKit media swap, behind the flag) lands in phase 2. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>