Add numbered pagination and redesign the IT/EN language switch

Blog and category archives now show a numbered page list (first, last,
current +/-1, collapsing gaps into an ellipsis) instead of only
previous/next — see shared/utils/pagination.ts's paginationRange().

Renders page links via NuxtLink's custom/v-slot API rather than letting
it render its own <a>: RouterLink's built-in active-class/aria-current
detection compares only the route's path, not its query string, so
every ?page=N link was incorrectly marked as the current page.

The language switch now shows both "Italiano / English" at all times,
with the current one as plain non-interactive text and the other as a
link, moved to the header's top-right corner instead of stacked under
the logo.

frontend/shared/utils/i18n.ts

@@ -20,7 +20,11 @@ export const STRINGS = {
     footerFollowAriaLabel: 'Seguici',
     contactLabel: 'Contatti:',
     copyright: 'Tutti i diritti riservati.',
-    langSwitchLabel: 'English',
+    langSwitch: {
+      ariaLabel: 'Lingua del sito',
+      it: 'Italiano',
+      en: 'English',
+    },
     home: {
       heading: "La fine dell'Unione Europea per come l'abbiamo conosciuta.",
       img1Alt: 'Manifesti e scritte contro le banche durante una crisi bancaria',
@@ -43,6 +47,7 @@ export const STRINGS = {
       prevPage: 'Pagina precedente',
       nextPage: 'Pagina successiva',
       pageOf: 'Pagina {current} di {total}',
+      goToPage: 'Vai a pagina {page}',
       paginationAriaLabel: 'Paginazione',
     },
     category: {
@@ -71,7 +76,11 @@ export const STRINGS = {
     footerFollowAriaLabel: 'Follow us',
     contactLabel: 'Contact:',
     copyright: 'All rights reserved.',
-    langSwitchLabel: 'Italiano',
+    langSwitch: {
+      ariaLabel: 'Site language',
+      it: 'Italiano',
+      en: 'English',
+    },
     home: {
       heading: "The end of the European Union as we've known it.",
       img1Alt: 'Banners and graffiti against banks during a banking crisis',
@@ -94,6 +103,7 @@ export const STRINGS = {
       prevPage: 'Previous page',
       nextPage: 'Next page',
       pageOf: 'Page {current} of {total}',
+      goToPage: 'Go to page {page}',
       paginationAriaLabel: 'Pagination',
     },
     category: {

frontend/shared/utils/pagination.ts

@@ -0,0 +1,37 @@
+export type PaginationItem = number | 'ellipsis'
+
+function range(start: number, end: number): number[] {
+  const length = end - start + 1
+  return Array.from({ length }, (_, i) => start + i)
+}
+
+/**
+ * Windowed page list for numbered pagination: always shows the first and
+ * last page, the current page and its immediate siblings, collapsing any
+ * gap into a single 'ellipsis' marker. Returns every page when the total
+ * is small enough that no collapsing is needed.
+ */
+export function paginationRange(current: number, total: number, siblingCount = 1): PaginationItem[] {
+  if (total <= 0) return []
+
+  const totalVisible = siblingCount * 2 + 5 // first + last + current + 2 siblings + 2 ellipses
+  if (totalVisible >= total) return range(1, total)
+
+  const leftSibling = Math.max(current - siblingCount, 1)
+  const rightSibling = Math.min(current + siblingCount, total)
+
+  const showLeftEllipsis = leftSibling > 2
+  const showRightEllipsis = rightSibling < total - 1
+
+  if (!showLeftEllipsis && showRightEllipsis) {
+    const leftRange = range(1, 3 + siblingCount * 2)
+    return [...leftRange, 'ellipsis', total]
+  }
+
+  if (showLeftEllipsis && !showRightEllipsis) {
+    const rightRange = range(total - (3 + siblingCount * 2) + 1, total)
+    return [1, 'ellipsis', ...rightRange]
+  }
+
+  return [1, 'ellipsis', ...range(leftSibling, rightSibling), 'ellipsis', total]
+}