Add debugging to help diagnose why the application isn't loading

Add comprehensive logging and error handling to the client-side entry point and index.html to identify and report issues preventing the React application from mounting.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 890577b1-c154-40a4-a177-a0c6d55320c3
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/8cc42625-c1f5-4e43-99bd-77f2c4dedee2/890577b1-c154-40a4-a177-a0c6d55320c3/DyHCx4q

client/src/main.tsx

@@ -2,6 +2,8 @@ import { createRoot } from "react-dom/client";
 import App from "./App";
 import "./index.css";
 
+console.log('🎬 main.tsx starting...');
+
 // Registracija Service Worker-ja za PWA funkcionalnost
 if ('serviceWorker' in navigator) {
   window.addEventListener('load', () => {
@@ -15,4 +17,35 @@ if ('serviceWorker' in navigator) {
   });
 }
 
-createRoot(document.getElementById("root")!).render(<App />);
+try {
+  const rootElement = document.getElementById("root");
+  console.log('🎯 Root element found:', rootElement);
+  
+  if (!rootElement) {
+    throw new Error('Root element not found');
+  }
+  
+  console.log('🚀 Creating React root...');
+  const root = createRoot(rootElement);
+  
+  console.log('🎭 Rendering App component...');
+  root.render(<App />);
+  
+  console.log('✅ React app mounted successfully');
+} catch (error) {
+  console.error('❌ Failed to mount React app:', error);
+  
+  // Fallback error display
+  const rootElement = document.getElementById("root");
+  if (rootElement) {
+    rootElement.innerHTML = `
+      <div style="color: red; padding: 20px; font-family: Arial; text-align: center; background: #000; height: 100vh; display: flex; align-items: center; justify-content: center;">
+        <div>
+          <h1>Critical Error: React app failed to start</h1>
+          <p>Error: ${error instanceof Error ? error.message : 'Unknown error'}</p>
+          <p>Check browser console for details</p>
+        </div>
+      </div>
+    `;
+  }
+}