fix: reconnect WS on session switch instead of deleting dead sessions

frontend/src/components/SessionChat.tsx

@@ -38,6 +38,11 @@ export default function SessionChat({ sessionId, isActive, onSessionDead }: Sess
   const prevActiveRef = useRef(isActive);
   useEffect(() => {
     if (isActive && !prevActiveRef.current) {
+      // Force reconnect if WS is dead (e.g. retries exhausted while on another session)
+      if (transport && !transport.isWebSocketConnected()) {
+        transport.connectToSession(sessionId);
+      }
+
       const store = useAgentStore.getState();
 
       // Sync WebSocket connection state

frontend/src/lib/ws-chat-transport.ts

@@ -313,8 +313,7 @@ export class WebSocketChatTransport implements ChatTransport<UIMessage> {
       if (!noRetry.includes(evt.code) && this.currentSessionId === sessionId) {
         this.retries += 1;
         if (this.retries > WS_MAX_RETRIES) {
-          logger.warn('WS max retries reached');
-          this.sideChannel.onSessionDead(sessionId);
+          logger.warn('WS max retries reached, will reconnect on session switch');
           return;
         }
         this.reconnectTimeout = setTimeout(() => {