feat: add PWA support with manifest and service worker

client/vite.config.ts

@@ -1,9 +1,47 @@
 import { defineConfig } from 'vite';
 import react from '@vitejs/plugin-react-swc';
 import { fileURLToPath, URL } from 'node:url';
+import { VitePWA } from 'vite-plugin-pwa';
+
+const pwaManifest = {
+  name: 'Traveling Around The World',
+  short_name: 'Travel Map',
+  description: '記錄旅程、管理旅遊分類並在地圖上標記足跡的 PWA。',
+  lang: 'zh-Hant',
+  start_url: '/',
+  scope: '/',
+  display: 'standalone',
+  background_color: '#ffffff',
+  theme_color: '#0f172a',
+  icons: [
+    {
+      src: '/icons/icon-192.svg',
+      sizes: '192x192',
+      type: 'image/svg+xml',
+      purpose: 'any'
+    },
+    {
+      src: '/icons/icon-512.svg',
+      sizes: '512x512',
+      type: 'image/svg+xml',
+      purpose: 'any maskable'
+    }
+  ]
+};
 
 export default defineConfig({
-  plugins: [react()],
+  plugins: [
+    react(),
+    VitePWA({
+      registerType: 'autoUpdate',
+      includeAssets: ['favicon.svg', 'icons/icon-192.svg', 'icons/icon-512.svg'],
+      manifest: pwaManifest,
+      workbox: {
+        navigateFallback: '/index.html',
+        globPatterns: ['**/*.{js,css,html,svg,png,ico,json}']
+      }
+    })
+  ],
   resolve: {
     alias: {
       '@shared': fileURLToPath(new URL('../shared', import.meta.url))