feat(admin): add initial admin dashboard structure

This commit introduces the foundational structure for the new admin dashboard.

- Utilizes @nuxt/ui to build the dashboard layout, including a collapsible sidebar and navigation.
- Adds initial pages for the dashboard, news, events, and hall of fame management.
- Implements a composable `useDashboardSidebarLinks` for managing sidebar navigation.
- Refactors the default layout by integrating the header and footer directly.
- Swaps the primary and secondary theme colors across the application.

app/components/index/News.vue

@@ -5,11 +5,11 @@
       <h2 class="text-2xl font-bold text-gray-900 mb-6">最新新闻与公告</h2>
       <div class="grid md:grid-cols-3 gap-6">
         <article v-for="n in news" :key="n.id" @click="jumpToNewsDetail(n.stem)"
-          class="bg-primary/10 rounded-xl shadow cursor-pointer transition transform hover:-translate-y-1 hover:scale-105 hover:shadow-xl duration-300 ease-in-out">
+          class="bg-secondary/10 rounded-xl shadow cursor-pointer transition transform hover:-translate-y-1 hover:scale-105 hover:shadow-xl duration-300 ease-in-out">
           <img class="rounded-xl" :src="n.cover" :alt="n.title">
           <div class="p-5">
             <h3 class="font-semibold mb-2">{{ n.title }}</h3>
-            <div class="px-1 w-max bg-primary/25 border-primary border-2 rounded-xl text-secondary text-sm mb-2">{{
+            <div class="px-1 w-max bg-secondary/25 border-secondary border-2 rounded-xl text-primary text-sm mb-2">{{
               useChineseDateFormat(n.date) }}</div>
             <p class="text-sm text-gray-600">{{ n.description }}</p>
           </div>