feat(ui): implement dynamic dropdown navigation and refactor project cards

Replaced the static navigation with a dynamic, internationalized dropdown menu powered by a new `useNavLinks` composable. The
navigation items are now sourced from i18n files. The featured project cards on the homepage have been refactored to use the
`<UPageCard>` component, and the content schema is updated with `spotlight` and `highlight` options for enhanced display.

content/zh-CN/index.yml

@@ -34,6 +34,7 @@ featuredProjects:
       description: "2022 年疫情期间，为马来西亚留学生开发的返校攻略网站。帮助 5000+ 名留学生顺利返校。并获得马来西亚外交部推荐。"
       image: "http://img.tootaio.com/i/2025/11/05/d9kcma.png"
       demoLink: "https://tootaio.github.io"
+      spotlight: true
     - title: "光追"
       description: "基于 Godot 引擎的 2023 年吉比特高校挑战赛参赛作品。"
       image: "https://img.tootaio.com/i/2025/09/26/j2swgq.png"