add zh_cn

components/providers/intl-provider.tsx

@@ -14,6 +14,7 @@ import nlMessages from '@/locales/nl/common.json';
 import plMessages from '@/locales/pl/common.json';
 import ptMessages from '@/locales/pt/common.json';
 import ruMessages from '@/locales/ru/common.json';
+import zhMessages from '@/locales/zh/common.json';
 
 // Pre-loaded translations (loaded at build time, not runtime)
 const ALL_MESSAGES = {
@@ -28,6 +29,7 @@ const ALL_MESSAGES = {
   pl: plMessages,
   pt: ptMessages,
   ru: ruMessages,
+  zh: zhMessages,
 };
 
 interface IntlProviderProps {

components/ui/language-switcher.tsx

@@ -19,7 +19,8 @@ export function LanguageSwitcher({ className }: { className?: string }) {
     { value: 'nl', label: 'Nederlands' },
     { value: 'pl', label: 'Polski' },
     { value: 'pt', label: 'Português' },
-    { value: 'ru', label: 'Русский' }
+    { value: 'ru', label: 'Русский' },
+    { value: 'zh', label: '简体中文' }
   ];
 
   return (