fix(frontend): handle websocket disconnect issue (#11144)

## Changes 🏗️

I found that if I logged out while an agent was running, sometimes
Webscokets would keep open connections but fail to connect ( given there
is no token anymore ) and cause strange behavior down the line on the
login screen.

Two root causes behind after inspecting the browser logs 🧐 
- WebSocket connections were attempted with an empty token right after
logout, yielding `wss://.../ws?token=` and repeated `1006/connection`
refused loops.
- During logout, sockets in `CONNECTING` state weren’t being closed, so
the browser kept trying to finish the handshake and were reattempted
shortly after failing

Trying to fix this like:
- Guard `connectWebSocket()` to no-op if a logout/disconnect intent is
set, and to skip connecting when no token is available.
- Treat `CONNECTING` sockets as closeable in `disconnectWebSocket()` and
clear `wsConnecting` to avoid stale pending Promises
- Left existing heartbeat/reconnect logic intact, but it now won’t run
when we’re logging out or when we can’t get a token.

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  - [x] Login and run an agent that takes long to run
  - [x] Logout
  - [x] Check the browser console and you don't see any socket errors
  - [x] The login screen behaves ok   

### For configuration changes:

Noop

autogpt_platform/frontend/src/lib/autogpt-server-api/client.ts

@@ -1126,6 +1126,11 @@ export default class BackendAPI {
   }
 
   async connectWebSocket(): Promise<void> {
+    // Do not attempt to connect if a disconnect intent is present (e.g., during logout)
+    if (this._hasDisconnectIntent()) {
+      return;
+    }
+
     this.isIntentionallyDisconnected = false;
     return (this.wsConnecting ??= new Promise(async (resolve, reject) => {
       try {
@@ -1139,7 +1144,19 @@ export default class BackendAPI {
           }
         } catch (error) {
           console.warn("Failed to get token for WebSocket connection:", error);
-          // Continue with empty token, connection might still work
+          // Intentionally fall through; we'll bail out below if no token is available
+        }
+
+        // If we don't have a token, skip attempting a connection.
+        if (!token) {
+          console.info(
+            "[BackendAPI] Skipping WebSocket connect: no auth token available",
+          );
+          // Resolve first, then clear wsConnecting to avoid races for awaiters
+          resolve();
+          this.wsConnecting = null;
+          this.webSocket = null;
+          return;
         }
 
         const wsUrlWithToken = `${this.wsUrl}?token=${token}`;
@@ -1178,6 +1195,9 @@ export default class BackendAPI {
           if (!wasIntentional) {
             this.wsOnDisconnectHandlers.forEach((handler) => handler());
             setTimeout(() => this.connectWebSocket().then(resolve), 1000);
+          } else {
+            // Ensure pending connect calls settle on intentional close
+            resolve();
           }
         };
 
@@ -1197,9 +1217,14 @@ export default class BackendAPI {
   disconnectWebSocket() {
     this.isIntentionallyDisconnected = true;
     this._stopWSHeartbeat(); // Stop heartbeat when disconnecting
-    if (this.webSocket && this.webSocket.readyState === WebSocket.OPEN) {
+    if (
+      this.webSocket &&
+      (this.webSocket.readyState === WebSocket.OPEN ||
+        this.webSocket.readyState === WebSocket.CONNECTING)
+    ) {
       this.webSocket.close();
     }
+    this.wsConnecting = null;
   }
 
   private _hasDisconnectIntent(): boolean {