🌐 Add full i18n system frontend + API (Story 1.3)

Nuxt i18n with lazy-loaded JSON files, localized routes, hreflang SEO tags,
LanguageSwitcher component. Laravel SetLocale middleware, HasTranslations trait,
API Resources and Controllers for projects/skills with Accept-Language support.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/nuxt.config.ts

@@ -24,9 +24,25 @@ export default defineNuxtConfig({
   },
 
   i18n: {
-    locales: ['fr', 'en'],
+    locales: [
+      { code: 'fr', iso: 'fr-FR', file: 'fr.json', name: 'Français' },
+      { code: 'en', iso: 'en-US', file: 'en.json', name: 'English' },
+    ],
     defaultLocale: 'fr',
     strategy: 'prefix_except_default',
+    lazy: true,
+    langDir: '../i18n/',
+    detectBrowserLanguage: false,
+    pages: {
+      'projets/index': { en: '/projects' },
+      'projets/[slug]': { en: '/projects/[slug]' },
+      'competences': { en: '/skills' },
+      'temoignages': { en: '/testimonials' },
+      'parcours': { en: '/journey' },
+      'contact': { en: '/contact' },
+      'resume': { en: '/resume' },
+    },
+    baseUrl: process.env.NUXT_PUBLIC_SITE_URL || 'https://skycel.fr',
   },
 
   app: {