[i18n] Add Brazilian Portuguese (pt-BR) translation

[joaoback]

🌐 Brazilian Portuguese (pt-BR) Translation

Hi! I'd like to propose adding a Brazilian Portuguese (pt-BR) translation for the LightRAG frontend.

What I've done

I have a complete translation of all 465 lines of the locale file (en.json → [pt-br.json], covering every section of the interface:

• Settings — Language, Theme (Light/Dark/System)
• Header — Navigation items, theme toggle
• Login — Full login screen (fields, messages, errors, guest mode)
• Common — Generic actions (Cancel, Save)
• Document Panel — Clear/Delete/Upload documents, document manager, pipeline status
• Graph Panel — 23 node types, sidebar settings, zoom/layout controls, status card, properties view (nodes/edges/merge), search, graph labels
• Retrieve Panel — Chat messages (copy, thinking), retrieval interface, full query settings (modes, response format, tokens, history, streaming, reranking)
• API — Documentation loading, API key alert
• Pagination — Full navigation labels

Translation criteria

• Natural Brazilian Portuguese — Not literal translations; phrasing follows how native pt-BR speakers actually use software
• Technical terms preserved — Industry-standard terms kept as-is: LLM, Embedding, Reranker, Pipeline, Chunks, KV, Top K, Bypass, Streaming, Workspace
• Consistency — Uniform terminology throughout (e.g., "nó" for node, "aresta" for edge, "grafo" for graph)
• Placeholders intact — All {{variables}} preserved exactly as in the original
• JSON structure — Identical key structure to en.json, only values translated

Why pt-BR?

Brazil has a large and growing developer and AI community. Portuguese is the 6th most spoken language worldwide (~260M speakers), with Brazil accounting for the vast majority. Adding pt-BR would significantly expand LightRAG's accessibility.

Ready to contribute

I have the full [pt-br.json] file ready. If you can point me to the contribution guidelines or grant the necessary permissions, I'd be happy to submit a PR right away.

Let me know how you'd like to proceed! 🚀