fix: enable offline page caching in service worker for PWA refresh support

Navigation requests had no caching rule, so refreshing offline showed the
browser's default "you are offline" page. Add NetworkFirst runtime caching
for navigations (3s timeout), cache Google Fonts for offline use, remove
conflicting static webmanifest in favor of the plugin-generated one.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vite.config.ts

@@ -40,8 +40,17 @@ export default defineConfig({
 			},
 			workbox: {
 				globPatterns: ['client/**/*.{js,css,ico,png,svg,webp,woff,woff2}'],
-				navigateFallback: '/',
+				navigateFallback: null,
 				runtimeCaching: [
+					{
+						urlPattern: ({ request }) => request.mode === 'navigate',
+						handler: 'NetworkFirst',
+						options: {
+							cacheName: 'pages-cache',
+							networkTimeoutSeconds: 3,
+							expiration: { maxEntries: 50, maxAgeSeconds: 30 * 24 * 60 * 60 }
+						}
+					},
 					{
 						urlPattern: /\/api\/notes\/.*\/attachments\?attachmentId=/,
 						handler: 'CacheFirst',
@@ -57,6 +66,14 @@ export default defineConfig({
 							cacheName: 'api-cache',
 							expiration: { maxEntries: 50, maxAgeSeconds: 300 }
 						}
+					},
+					{
+						urlPattern: /^https?:\/\/fonts\.(?:googleapis|gstatic)\.com\/.*/,
+						handler: 'CacheFirst',
+						options: {
+							cacheName: 'google-fonts-cache',
+							expiration: { maxEntries: 10, maxAgeSeconds: 365 * 24 * 60 * 60 }
+						}
 					}
 				]
 			}