fix(web): harden typed SPA chat lifecycle

Co-Authored-By: Claude Haiku 4.5 <[email protected]>

apps/web/src/lib/socket.ts

@@ -16,12 +16,12 @@ export function getSocket(): ChatSocket {
       transports: ['websocket', 'polling'],
     }) as unknown as ChatSocket;
 
-    // Reset singleton reference when socket is fully closed so the next
-    // getSocket() call creates a fresh instance instead of returning a
-    // closed/dead socket.
-    socket.on('disconnect', () => {
-      socket = null;
-    });
+    // A transient `disconnect` (network blip, server restart) must NOT null
+    // the singleton: socket.io-client auto-reconnects this same instance,
+    // and its listeners stay registered across that reconnect. Nulling here
+    // previously orphaned those listeners on the next getSocket() call by
+    // handing back a brand-new, unconnected instance. Only destroySocket()
+    // (an explicit, intentional teardown) may reset the singleton.
   }
   return socket;
 }