feat: add periodic game.status broadcast and live status REST endpoint

Add 20-second game.status WebSocket heartbeat from active shard monitors
containing full game state, and GET /status-live REST endpoint for on-demand
polling. Fix missing token destructuring in SessionInfo causing crash.
Relax frontend polling from 3s to 60s since WebSocket events now cover
real-time updates. Bump version to 0.6.0.

Made-with: Cursor

backend/utils/ecast-shard-client.js

@@ -90,6 +90,38 @@ class EcastShardClient {
     this.seq = 0;
     this.appTag = null;
     this.reconnecting = false;
+    this.statusInterval = null;
+  }
+
+  getSnapshot() {
+    return {
+      sessionId: this.sessionId,
+      gameId: this.gameId,
+      roomCode: this.roomCode,
+      appTag: this.appTag,
+      maxPlayers: this.maxPlayers,
+      playerCount: this.playerCount,
+      players: [...this.playerNames],
+      lobbyState: this.lobbyState,
+      gameState: this.gameState,
+      gameStarted: this.gameStarted,
+      gameFinished: this.gameFinished,
+      monitoring: true,
+    };
+  }
+
+  startStatusBroadcast() {
+    this.stopStatusBroadcast();
+    this.statusInterval = setInterval(() => {
+      this.onEvent('game.status', this.getSnapshot());
+    }, 20000);
+  }
+
+  stopStatusBroadcast() {
+    if (this.statusInterval) {
+      clearInterval(this.statusInterval);
+      this.statusInterval = null;
+    }
   }
 
   buildReconnectUrl() {
@@ -152,6 +184,8 @@ class EcastShardClient {
       lobbyState: this.lobbyState,
       gameState: this.gameState,
     });
+
+    this.startStatusBroadcast();
   }
 
   handleEntityUpdate(result) {
@@ -406,6 +440,7 @@ class EcastShardClient {
   }
 
   disconnect() {
+    this.stopStatusBroadcast();
     if (this.ws) {
       try {
         this.ws.close(1000, 'Monitor stopped');
@@ -569,4 +604,9 @@ async function cleanupAllShards() {
   console.log('[Shard Monitor] Cleaned up all active shards');
 }
 
-module.exports = { EcastShardClient, startMonitor, stopMonitor, cleanupAllShards };
+function getMonitorSnapshot(sessionId, gameId) {
+  const client = activeShards.get(`${sessionId}-${gameId}`);
+  return client ? client.getSnapshot() : null;
+}
+
+module.exports = { EcastShardClient, startMonitor, stopMonitor, cleanupAllShards, getMonitorSnapshot };