🌐 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/app/composables/useApi.ts

@@ -0,0 +1,18 @@
+export const useApi = () => {
+  const config = useRuntimeConfig()
+  const { locale } = useI18n()
+
+  const apiFetch = async <T>(endpoint: string, options: Record<string, any> = {}) => {
+    return await $fetch<T>(`${config.public.apiUrl}${endpoint}`, {
+      ...options,
+      headers: {
+        'X-API-Key': config.public.apiKey as string,
+        'Accept-Language': locale.value,
+        'Content-Type': 'application/json',
+        ...options.headers,
+      },
+    })
+  }
+
+  return { apiFetch }
+}

frontend/app/composables/useLocale.ts

@@ -0,0 +1,29 @@
+export const useLocale = () => {
+  const { locale, locales, setLocale } = useI18n()
+  const switchLocalePath = useSwitchLocalePath()
+  const localePath = useLocalePath()
+
+  const currentLocale = computed(() => locale.value)
+
+  const availableLocales = computed(() =>
+    (locales.value as Array<{ code: string; name: string }>).map(l => ({
+      code: l.code,
+      name: l.name,
+    }))
+  )
+
+  const switchLocale = (code: string) => {
+    return navigateTo(switchLocalePath(code))
+  }
+
+  const localizedPath = (path: string) => {
+    return localePath(path)
+  }
+
+  return {
+    currentLocale,
+    availableLocales,
+    switchLocale,
+    localizedPath,
+  }
+}