refactor: enhance session management and room joining logic in WebSocket handling

public/js/ws.js

@@ -4,6 +4,8 @@ let ws;
 let reconnectAttempts = 0;
 let reconnectTimer = null;
 const outbox = [];
+let sessionId = localStorage.getItem('sessionId') || null;
+let lastRoomId = localStorage.getItem('lastRoomId') || null;
 
 export function wsIsOpen() { return ws && ws.readyState === WebSocket.OPEN; }
 export function sendMsg(obj) { if (wsIsOpen()) ws.send(JSON.stringify(obj)); else outbox.push(obj); }
@@ -20,6 +22,10 @@ export function connectWS(onMessage) {
   ws = new WebSocket(url);
   ws.addEventListener('open', () => {
     reconnectAttempts = 0;
+    // Try to resume session immediately on (re)connect
+    if (sessionId) {
+      try { ws.send(JSON.stringify({ type: 'resume', sessionId })); } catch {}
+    }
     setTimeout(() => { while (outbox.length && wsIsOpen()) { try { ws.send(JSON.stringify(outbox.shift())); } catch { break; } } }, 100);
   });
   ws.addEventListener('message', (ev) => onMessage(ev));
@@ -33,3 +39,15 @@ window.addEventListener('online', () => {
     // Kick off a reconnect by calling connectWS from app main again
   }
 });
+
+// Helpers to update cached ids from other modules
+export function cacheSessionId(id) {
+  if (!id) return;
+  sessionId = id;
+  try { localStorage.setItem('sessionId', id); } catch {}
+}
+export function cacheLastRoomId(id) {
+  if (!id) return;
+  lastRoomId = id;
+  try { localStorage.setItem('lastRoomId', id); } catch {}
+}