Add PWA support with manifest and TWA integration. Update Vite PWA plugin configuration and scripts for building and updating TWA.

index.html

@@ -6,6 +6,7 @@
     <link rel="icon" type="image/svg+xml" href="/favicons/favicon.svg" />
     <link rel="shortcut icon" href="/favicons/favicon.ico" />
     <link rel="apple-touch-icon" sizes="180x180" href="/favicons/apple-touch-icon.png" />
+    <link rel="manifest" href="/manifest.json" />
     <meta name="apple-mobile-web-app-title" content="Truck Wash Kundeportal" />
     <link rel="stylesheet" href="bulma/css/bulma.min.css">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">