Add Portuguese (pt and pt-BR) language support

[vinipereira-io]

Adds support for Portuguese (pt) and Brazilian Portuguese (pt-BR).

• Included langs/pt.json and langs/pt-BR.json
• Updated entry-node.js to support both
• Revised README to list supported languages
• All tests passing ✅

Why both pt and pt-BR?

Although both variants share the same base language, Brazilian and European Portuguese differ in important ways when it comes to nationalities.

Examples:

• "South Korean" → commonly "sul-coreano" in Brazil, but sometimes "coreano do sul" or more formal versions in Portugal.
• "American" → usually "americano" in Brazil, while "norte-americano" or "estadunidense" may be more common in European Portuguese.

Why is this important?

• Portuguese is spoken by over 260 million people, with Brazil accounting for over 80% of all speakers.
• Apps targeting Brazilian audiences should use terminology aligned with local language and cultural standards.
• Separating pt and pt-BR improves the quality and flexibility of internationalization.