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.

app/pages/index.vue

@@ -23,26 +23,24 @@
         :items="page?.featuredProjects.projects"
         :ui="{ item: 'basis-full sm:basis-1/2 lg:basis-1/3' }"
       >
-        <UCard class="my-2">
-          <template #header>
-            <h3 class="text-2xl font-bold">{{ item.title }}</h3>
-          </template>
-          <template #default>
-            <img :src="item.image" :alt="item.title" />
-            <p class="mt-2 line-clamp-3">{{ item.description }}</p>
-          </template>
-          <template #footer>
-            <UButton
-              v-if="item.demoLink"
-              :href="item.demoLink"
-              target="_blank"
-              rel="noopener"
-              size="sm"
-            >
-              {{ $t("index.featuredProjects.viewDemo") }}
-            </UButton>
-          </template>
-        </UCard>
+        <UPageCard
+          class="my-2"
+          :title="item.title"
+          :description="item.description"
+          :highlight="item.highlight"
+          :spotlight="item.spotlight"
+        >
+          <img :src="item.image" :alt="item.title" />
+          <UButton
+            v-if="item.demoLink"
+            :href="item.demoLink"
+            target="_blank"
+            rel="noopener"
+            size="sm"
+          >
+            {{ $t("index.featuredProjects.viewDemo") }}
+          </UButton>
+        </UPageCard>
       </UCarousel>
     </UPageSection>