feat: add locale display names in selector (#6561)

Author: fairlighteth

libs/common-const/src/locales.ts

@@ -8,3 +8,10 @@ export const SUPPORTED_LOCALES = [
 export type SupportedLocale = (typeof SUPPORTED_LOCALES)[number] | 'pseudo'
 
 export const DEFAULT_LOCALE: SupportedLocale = 'en-US'
+
+// Override display names shown in language selectors to ensure consistent wording
+export const LOCALE_DISPLAY_NAMES: Partial<Record<SupportedLocale, string>> = {
+  'en-US': 'English (US)',
+  'es-ES': 'Español (España)',
+  'ru-RU': 'Русский (Россия)',
+}

libs/ui/src/pure/MenuBar/index.tsx

@@ -16,6 +16,7 @@ import IMG_ICON_MENU_DOTS from '@cowprotocol/assets/images/menu-grid-dots.svg'
 import IMG_ICON_MENU_HAMBURGER from '@cowprotocol/assets/images/menu-hamburger.svg'
 import IMG_ICON_SETTINGS_GLOBAL from '@cowprotocol/assets/images/settings-global.svg'
 import IMG_ICON_X from '@cowprotocol/assets/images/x.svg'
+import { LOCALE_DISPLAY_NAMES } from '@cowprotocol/common-const'
 import { useMediaQuery, useOnClickOutside } from '@cowprotocol/common-hooks'
 import { addBodyClass, removeBodyClass } from '@cowprotocol/common-utils'
 
@@ -102,6 +103,11 @@ const DAO_NAV_ITEMS: MenuItem[] = [
 ]
 
 const getLanguageName = (locale: string): string => {
+  const override = LOCALE_DISPLAY_NAMES[locale as keyof typeof LOCALE_DISPLAY_NAMES]
+  if (override) {
+    return override
+  }
+
   const display = new Intl.DisplayNames([locale], { type: 'language' })
   const languageName = display.of(locale)