Only show locale switcher in development mode

src/components/locale-switcher/LocaleSwitcher.tsx

@@ -2,6 +2,9 @@ import React from 'react';
 import { useTranslation } from 'react-i18next';
 
 export const LocaleSwitcher: React.FC = () => {
+  if (import.meta.env.MODE === 'production') {
+    return null;
+  }
   const { t, i18n } = useTranslation();
   return (
     <select