feat(i18n): add Portuguese (Brazil) locale (pt-BR) (#6943)

Finalmente o idioma em Portugues do Brasil verá a luz do dia (se tudo
correr bem).

What has been done:

- Added pt-BR to .i18nrc.cjs and settings
- Included loaders in src/i18n.ts and apps/desktop-ui/src/i18n.ts
- Now Portuguese (BR) is displayed in the language selector
- Created empty main.json, commands.json, settings.json and
nodeDefs.json files to be populated by CI

- Checklist: the language appears in the dropdown list, selection occurs
without errors, the fallback to English, in case technical terms have no
translation, is working correctly.

- I will maintain the pt-br translation and review for as long as
necessary.

---------

Co-authored-by: Comfy Contributor <dev@example.com>

src/platform/settings/constants/coreSettings.ts

@@ -416,7 +416,8 @@ export const CORE_SETTINGS: SettingParams[] = [
       { value: 'fr', text: 'Français' },
       { value: 'es', text: 'Español' },
       { value: 'ar', text: 'عربي' },
-      { value: 'tr', text: 'Türkçe' }
+      { value: 'tr', text: 'Türkçe' },
+      { value: 'pt-BR', text: 'Português (BR)' }
     ],
     defaultValue: () => navigator.language.split('-')[0] || 'en'
   },