Remove i18n, keep only Italian and rely on browser translation

The interface was translated in en/it/es/fr via @nuxtjs/i18n. Drop the
module, the locale files, and the language switcher: the UI is now
static Italian text, with translation for foreign visitors left to the
Google Translate browser extension instead of the app.

frontend/app/pages/category/[slug].vue

@@ -1,7 +1,6 @@
 <script setup lang="ts">
 import type { ArticleSummary, Paginated, Category } from '#shared/types/blog'
 
-const { t } = useI18n()
 const route = useRoute()
 const slug = route.params.slug as string
 
@@ -27,7 +26,7 @@ const canonical = computed(
 
 useSeoMeta({
   title: category.value.name,
-  description: () => t('list.categoryDescription', { name: category.value?.name ?? '' }),
+  description: () => `Tutti gli articoli nella categoria ${category.value?.name ?? ''}.`,
   ogType: 'website',
 })
 
@@ -37,13 +36,13 @@ useHead({ link: [{ rel: 'canonical', href: canonical }] })
 <template>
   <div>
     <header class="page-header">
-      <p class="kicker">{{ $t('list.category') }}</p>
+      <p class="kicker">Categoria</p>
       <h1>{{ category?.name }}</h1>
     </header>
 
-    <p v-if="error">{{ $t('list.failed') }}</p>
+    <p v-if="error">Non è stato possibile caricare gli articoli. Riprova più tardi.</p>
 
-    <p v-else-if="!data?.items.length">{{ $t('list.categoryEmpty') }}</p>
+    <p v-else-if="!data?.items.length">Non ci sono articoli in questa categoria.</p>
 
     <template v-else>
       <ul class="card-grid">
@@ -52,19 +51,19 @@ useHead({ link: [{ rel: 'canonical', href: canonical }] })
         </li>
       </ul>
 
-      <nav v-if="data.pageCount > 1" class="pagination" :aria-label="$t('pagination.label')">
+      <nav v-if="data.pageCount > 1" class="pagination" aria-label="Paginazione">
         <NuxtLink v-if="data.page > 1" :to="{ query: { page: data.page - 1 } }" rel="prev">
-          {{ $t('pagination.previous') }}
+          Pagina precedente
         </NuxtLink>
         <span class="muted">
-          {{ $t('pagination.position', { page: data.page, total: data.pageCount }) }}
+          Pagina {{ data.page }} di {{ data.pageCount }}
         </span>
         <NuxtLink
           v-if="data.page < data.pageCount"
           :to="{ query: { page: data.page + 1 } }"
           rel="next"
         >
-          {{ $t('pagination.next') }}
+          Pagina successiva
         </NuxtLink>
       </nav>
     </template>