feat(pwa): M1 Task1 - PWA manifest 完善（lang zh-CN + iOS 图标与 meta）

Author: Aparencia

client/index.html

@@ -1,9 +1,14 @@
 <!doctype html>
-<html lang="en">
+<html lang="zh-CN">
   <head>
     <meta charset="UTF-8" />
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
-    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <link rel="apple-touch-icon" href="/pwa-192x192.png" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
+    <meta name="theme-color" content="#3b82f6" />
+    <meta name="apple-mobile-web-app-capable" content="yes" />
+    <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />
+    <meta name="mobile-web-app-capable" content="yes" />
     <title>熵减</title>
     <!-- 防主题闪烁：在 CSS 渲染前同步设置 data-theme（逻辑与 useThemeStore 一致） -->
     <script>

client/vite.config.ts

@@ -60,11 +60,12 @@ export default defineConfig(({ command }) => ({
     ...(isElectronBuild ? [electronBuildConfigPlugin()] : []),
     ...(isElectronBuild ? [] : [VitePWA({
       registerType: 'autoUpdate',
-      includeAssets: ['favicon.ico', 'apple-touch-icon.png', 'mask-icon.svg', 'offline.html'],
+      includeAssets: ['favicon.svg', 'offline.html'],
       manifest: {
         name: '熵减 - 学习伴侣',
         short_name: '熵减',
         description: '智能学习管理工具 - 笔记、闪卡、费曼学习法、番茄钟',
+        lang: 'zh-CN',
         theme_color: '#3b82f6',
         background_color: '#111827',
         display: 'standalone',