Update public/app.js

public/app.js

@@ -11,7 +11,7 @@ const state = {
   uploads: []
 };
 
-/* Correct line in app.js */
+// CRITICAL CHANGE: added the "path" option to ensure the client connects correctly
 const socket = io({ path: '/socket.io/', transports: ["websocket", "polling"] });
 
 /* ====== UI Helpers ====== */