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>

CODEOWNERS

@@ -54,10 +54,11 @@
 
 # Translations
 /src/locales/                                     @Yorha4D @KarryCharon @shinshin86 @Comfy-Org/comfy_maintainer @Comfy-org/comfy_frontend_devs
+/src/locales/pt-BR/                               @JonatanAtila @Yorha4D @KarryCharon @shinshin86
 
 # LLM Instructions (blank on purpose)
 .claude/
 .cursor/
 .cursorrules
 **/AGENTS.md
-**/CLAUDE.md
+**/CLAUDE.md