Simplify home page and nav to a single latest-article link

Home now shows only the latest article, pointing to the full list on
/blog instead of duplicating recent articles in a grid. Nav trims to
Home, Tutti gli articoli, and the corralito page; the footer drops the
now-redundant Categorie column.

frontend/app/layouts/default.vue

@@ -1,10 +1,4 @@
 <script setup lang="ts">
-import type { Category } from '#shared/types/blog'
-
-const { data: categories } = await useFetch<Category[]>('/api/categories', {
-  key: 'nav-categories',
-  default: () => [],
-})
 </script>
 
 <template>
@@ -24,12 +18,8 @@ const { data: categories } = await useFetch<Category[]>('/api/categories', {
       <nav class="site-nav" aria-label="Navigazione principale">
         <div class="container nav-inner">
           <ul>
+            <li><NuxtLink to="/">Home</NuxtLink></li>
             <li><NuxtLink to="/blog">Tutti gli articoli</NuxtLink></li>
-            <li v-for="category in categories" :key="category.slug">
-              <NuxtLink :to="`/category/${category.slug}`">
-                {{ category.name }}
-              </NuxtLink>
-            </li>
             <li><NuxtLink to="/come-difendersi-dal-corralito">Come difendersi dal corralito</NuxtLink></li>
           </ul>
         </div>
@@ -51,18 +41,6 @@ const { data: categories } = await useFetch<Category[]>('/api/categories', {
           </address>
         </div>
 
-        <nav class="footer-block" aria-label="Categorie">
-          <p class="kicker">Categorie</p>
-          <ul>
-            <li v-for="category in categories" :key="category.slug">
-              <NuxtLink :to="`/category/${category.slug}`">
-                {{ category.name }}
-              </NuxtLink>
-            </li>
-            <li v-if="!categories.length" class="muted">Ancora nessuna pubblicazione</li>
-          </ul>
-        </nav>
-
         <nav class="footer-block" aria-label="Naviga">
           <p class="kicker">Naviga</p>
           <ul>