Add PWA support using vite-plugin-pwa

Integrated the vite-plugin-pwa to enable Progressive Web App functionality. Added service worker registration, manifest configuration, and necessary assets like icons and favicon. This enhances offline capabilities and user experience.

frontend/vite.config.js

@@ -1,6 +1,34 @@
 import { defineConfig } from "vite";
 import react from "@vitejs/plugin-react";
+import { VitePWA } from "vite-plugin-pwa";
 
 export default defineConfig({
-  plugins: [react()],
+  plugins: [
+    react(),
+    VitePWA({
+      registerType: "autoUpdate",
+      includeAssets: [
+        "favicon.ico",
+        "icons/icon-512.png",
+        "marauders-map.jpg" // oder dein Hintergrund
+      ],
+      manifest: {
+        name: "Zauber-Detektiv Notizbogen",
+        short_name: "Notizbogen",
+        description: "Cluedo-Magie Sheet",
+        start_url: "/",
+        scope: "/",
+        display: "standalone",
+        background_color: "#1c140d",
+        theme_color: "#caa45a",
+        icons: [
+          { src: "/icons/icon-512.png", sizes: "512x512", type: "image/png" }
+        ]
+      },
+      workbox: {
+        // Caching-Default: die App-Shell wird offline verfügbar
+        globPatterns: ["**/*.{js,css,html,ico,png,jpg,jpeg,svg,webp}"],
+      }
+    })
+  ]
 });