Migrate to Vite 7, improve UI (Copy/Download), and enhance API security

src/index.jsx

@@ -0,0 +1,12 @@
+import React from 'react';
+import ReactDOM from 'react-dom/client';
+import 'bootstrap/dist/css/bootstrap.min.css';
+import './index.css';
+import App from './App';
+
+const root = ReactDOM.createRoot(document.getElementById('root'));
+root.render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>
+);