Add hand-rolled English support (/en/*) alongside the Italian site

PocketBase gains optional, manually-authored English fields on articles
and categories (same record, same slug), and the frontend serves an /en
counterpart of every dynamic route via thin page wrappers around shared
view components — no i18n library, consistent with the project's existing
minimalism stance for a two-locale site with ~20 UI strings.

An article/category with no translation 404s cleanly on its own /en
detail page and is filtered out of /en listings, and the header's
language-switch link falls back to the English blog index rather than a
dead link; resolving that requires a global route middleware, since the
layout's header renders before the page content in document order and so
can't react to state a page component sets during its own async setup.

tests/support/fixtures.ts

@@ -3,6 +3,7 @@
 export interface FixtureCategory {
   name: string
   slug: string
+  nameEn?: string
 }
 
 export interface FixtureArticle {
@@ -13,10 +14,12 @@ export interface FixtureArticle {
   /** `null` = draft (never returned by the public API). */
   publishedAt: string | null
   authorName?: string
+  titleEn?: string
+  contentEn?: string
 }
 
 export const FIXTURE_CATEGORIES: FixtureCategory[] = [
-  { name: 'Economia', slug: 'economia' },
+  { name: 'Economia', slug: 'economia', nameEn: 'Economy' },
   { name: 'Attualità', slug: 'attualita' },
 ]
 
@@ -28,6 +31,8 @@ export const FIXTURE_ARTICLES: FixtureArticle[] = [
     category: 'economia',
     publishedAt: '2025-01-15 10:00:00',
     authorName: 'Redazione',
+    titleEn: 'Published article',
+    contentEn: '# Title\n\nTest **markdown** body with [a link](https://example.com).',
   },
   {
     title: 'Articolo in bozza',
@@ -43,5 +48,6 @@ export const FIXTURE_ARTICLES: FixtureArticle[] = [
     category: 'attualita',
     publishedAt: '2025-02-01 08:00:00',
     authorName: 'Redazione',
+    // Deliberately no English translation: exercises the untranslated path.
   },
 ]

tests/support/pocketbase.ts

@@ -150,6 +150,8 @@ export async function startTestPocketbase(options: StartOptions = {}): Promise<T
         category: category?.id,
         publishedAt: article.publishedAt ?? '',
         authorName: article.authorName ?? '',
+        titleEn: article.titleEn ?? '',
+        contentEn: article.contentEn ?? '',
       }),
     })
     articles.push((await response.json()) as TestArticle)