Add PWA install support for mobile and desktop

Register service worker, install prompt UI, iOS meta tags, and document install steps in DEPLOY.md.

Co-authored-by: Cursor <cursoragent@cursor.com>

.vitepress/config.mts

@@ -1,6 +1,7 @@
 import path from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { defineConfig } from 'vitepress'
+import { createPwaPlugin } from './pwa.mts'
 import { missingAssetsPlugin } from './missing-assets-plugin.mjs'
 import { generateRewrites } from './rewrites.mts'
 import { generateSidebar } from './sidebar.mts'
@@ -37,6 +38,9 @@ export default defineConfig({
     ['meta', { name: 'msapplication-TileImage', content: '/apple-touch-icon.png' }],
     ['meta', { name: 'apple-mobile-web-app-title', content: '道德经' }],
     ['meta', { name: 'application-name', content: '道德经' }],
+    ['meta', { name: 'mobile-web-app-capable', content: 'yes' }],
+    ['meta', { name: 'apple-mobile-web-app-capable', content: 'yes' }],
+    ['meta', { name: 'apple-mobile-web-app-status-bar-style', content: 'black-translucent' }],
   ],
   themeConfig: {
     logo: { src: '/favicon.ico', width: 24, height: 24 },
@@ -54,7 +58,7 @@ export default defineConfig({
     },
   },
   vite: {
-    plugins: [missingAssetsPlugin()],
+    plugins: [missingAssetsPlugin(), createPwaPlugin()],
     server: {
       host: '0.0.0.0',
     },