🌐 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>

api/app/Http/Middleware/SetLocale.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class SetLocale
+{
+    protected array $supportedLocales = ['fr', 'en'];
+    protected string $fallbackLocale = 'fr';
+
+    public function handle(Request $request, Closure $next): Response
+    {
+        $locale = $this->parseAcceptLanguage($request->header('Accept-Language'));
+
+        app()->setLocale($locale);
+        $request->attributes->set('locale', $locale);
+
+        return $next($request);
+    }
+
+    protected function parseAcceptLanguage(?string $header): string
+    {
+        if (!$header) {
+            return $this->fallbackLocale;
+        }
+
+        $locales = [];
+        foreach (explode(',', $header) as $part) {
+            $part = trim($part);
+            if (preg_match('/^([a-z]{2})(?:-[A-Z]{2})?(?:;q=([0-9.]+))?$/i', $part, $matches)) {
+                $lang = strtolower($matches[1]);
+                $quality = isset($matches[2]) ? (float) $matches[2] : 1.0;
+                $locales[$lang] = $quality;
+            }
+        }
+
+        arsort($locales);
+
+        foreach (array_keys($locales) as $lang) {
+            if (in_array($lang, $this->supportedLocales)) {
+                return $lang;
+            }
+        }
+
+        return $this->fallbackLocale;
+    }
+}