add dropdown option for spanish locale

frontend/next-i18next.config.js

@@ -8,7 +8,7 @@ module.exports = {
   debug: false,
   i18n: {
     defaultLocale: "en",
-    locales: ["en", "ko", "fr", "pt-BR", "pt-PT"],
+    locales: ["en", "ko", "fr", "pt-BR", "pt-PT", "es"],
   },
   fallbackLng: {
     default: ["en"],

frontend/src/pages/settings/personal/[id].tsx

@@ -96,7 +96,7 @@ export default function PersonalSettings() {
                 <ListBox
                   isSelected={lang}
                   onChange={setLanguage}
-                  data={['en', 'ko', 'fr']}
+                  data={['en', 'ko', 'fr', 'es']}
                   text={`${t('common:language')}: `}
                 />
               </div>