fix: remove PWA service worker (was caching stale assets), add SW unregister

frontend/src/main.tsx

@@ -4,6 +4,15 @@ import App from './App';
 import './index.css';
 import './i18n';
 
+// Unregister any existing PWA service workers (PWA disabled — was caching stale assets)
+if ('serviceWorker' in navigator) {
+  navigator.serviceWorker.getRegistrations().then((registrations) => {
+    for (const reg of registrations) {
+      reg.unregister();
+    }
+  });
+}
+
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <React.StrictMode>
     <App />

frontend/vite.config.ts

@@ -1,66 +1,10 @@
 import { defineConfig } from 'vite';
 import react from '@vitejs/plugin-react';
 import { resolve } from 'path';
-import { VitePWA } from 'vite-plugin-pwa';
 
 export default defineConfig({
   plugins: [
     react(),
-    VitePWA({
-      registerType: 'autoUpdate',
-      includeAssets: ['favicon.svg', 'icon-192.svg', 'icon-512.svg'],
-      manifest: {
-        name: 'LeoCRM',
-        short_name: 'LeoCRM',
-        description: 'Mini-CRM für kleine Unternehmen',
-        theme_color: '#2563eb',
-        background_color: '#ffffff',
-        display: 'standalone',
-        orientation: 'portrait',
-        scope: '/',
-        start_url: '/',
-        icons: [
-          {
-            src: 'icon-192.svg',
-            sizes: '192x192',
-            type: 'image/svg+xml',
-            purpose: 'any maskable',
-          },
-          {
-            src: 'icon-512.svg',
-            sizes: '512x512',
-            type: 'image/svg+xml',
-            purpose: 'any maskable',
-          },
-        ],
-      },
-      workbox: {
-        globPatterns: ['**/*.{js,css,html,ico,png,svg,woff,woff2}'],
-        runtimeCaching: [
-          {
-            urlPattern: /^https:\/\/fonts\.googleapis\.com\/.*/i,
-            handler: 'CacheFirst',
-            options: {
-              cacheName: 'google-fonts-cache',
-              expiration: {
-                maxEntries: 10,
-                maxAgeSeconds: 60 * 60 * 24 * 365,
-              },
-            },
-          },
-          {
-            urlPattern: /\.(?:js|css|woff2?)$/i,
-            handler: 'StaleWhileRevalidate',
-            options: {
-              cacheName: 'static-resources',
-            },
-          },
-        ],
-      },
-      devOptions: {
-        enabled: false,
-      },
-    }),
   ],
   resolve: {
     alias: {