feat(i18n): add Romanian (ro) locale

Adds locales/ro/common.json and wires ro through routing, request,
intl-provider, the language switcher and the flag list. Plurals use
Romanian one/few/other forms.

i18n/request.ts

@@ -50,6 +50,9 @@ export default getRequestConfig(async ({ requestLocale }) => {
     case 'pt':
       messages = (await import('../locales/pt/common.json')).default;
       break;
+    case 'ro':
+      messages = (await import('../locales/ro/common.json')).default;
+      break;
     case 'ru':
       messages = (await import('../locales/ru/common.json')).default;
       break;

i18n/routing.ts

@@ -12,7 +12,7 @@ const localePrefix = (process.env.NEXT_PUBLIC_LOCALE_PREFIX ?? 'never') as
   | 'always'
   | 'as-needed';
 
-const SUPPORTED_LOCALES = ['cs', 'da', 'de', 'en', 'es', 'fr', 'hu', 'it', 'ja', 'ko', 'lv', 'nl', 'pl', 'pt', 'ru', 'tr', 'uk', 'zh'] as const;
+const SUPPORTED_LOCALES = ['cs', 'da', 'de', 'en', 'es', 'fr', 'hu', 'it', 'ja', 'ko', 'lv', 'nl', 'pl', 'pt', 'ro', 'ru', 'tr', 'uk', 'zh'] as const;
 
 // Fallback locale used when the visitor's Accept-Language header does not
 // match any supported locale (and no NEXT_LOCALE cookie is set yet). Admins