feat: 移除「关于本站」按钮与功能

- PublicLayout: 删除桌面导航/下拉菜单/页脚三处入口及空页脚,移除 about 导航类型与判断
- App: 移除 /about 路由及 AboutPage 引入
- 删除 pages/About 页面
- DocumentMeta: 移除 /about 的 meta 处理与 about 描述文案(中/英)
- i18n: 移除 aboutTitle / aboutIntro / footerAbout(中/英)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/components/DocumentMeta.tsx

@@ -15,7 +15,6 @@ const descriptions: Record<Lang, Record<string, string>> = {
       "按分类探索 ARK 官方资料，快速定位所需教材、公告、视频、图片与文件。",
     official: "查看 ARK 官方推荐资料，获取优先整理的重点内容与可信资源。",
     favorites: "收藏功能开发中，未来可在这里集中管理常用 ARK 资料。",
-    about: "了解 ARK 资料库的用途、资料范围与本站索引说明。",
     search: "在 ARK 资料库中搜索标题、分类、标签、简介、文件类型与正文内容。",
   },
   en: {
@@ -28,8 +27,6 @@ const descriptions: Record<Lang, Record<string, string>> = {
       "View official ARK recommendations and prioritized trusted resources.",
     favorites:
       "Favorites are in development and will help you manage commonly used ARK resources.",
-    about:
-      "Learn about the ARK Library purpose, resource scope, and indexing notes.",
     search:
       "Search ARK Library titles, categories, tags, summaries, file types, and body text.",
   },
@@ -136,13 +133,6 @@ function routeMeta(
     };
   }
 
-  if (pathname === "/about") {
-    return {
-      title: t("footerAbout"),
-      description: metaDescription(lang, "about"),
-    };
-  }
-
   return { title: t("brand"), description: metaDescription(lang, "home") };
 }