feat(app): introduce Hall of Fame section and refactor UI

This commit adds the '名人堂' (Hall of Fame) feature and removes the Element Plus dependency.

- feat(content): Add Hall of Fame section with a new content collection, homepage component, and detail pages.
- refactor(join-us): Rewrite the 'Join Us' form to remove Element Plus, using native elements and Reka UI. The form is
temporarily disabled.
- feat(ui): Display cover images on News and Events cards.
- chore: Integrate Umami for web analytics.
- fix: Correct minor text issues, including graduation year in the footer.

app/components/index/News.vue

@@ -5,11 +5,14 @@
       <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-white rounded-xl shadow p-5 cursor-pointer transition transform hover:-translate-y-1 hover:scale-105 hover:shadow-xl duration-300 ease-in-out">
-          <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">{{
-            useChineseDateFormat(n.date) }}</div>
-          <p class="text-sm text-gray-600">{{ n.description }}</p>
+          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">
+          <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">{{
+              useChineseDateFormat(n.date) }}</div>
+            <p class="text-sm text-gray-600">{{ n.description }}</p>
+          </div>
         </article>
       </div>
     </section>