Support for non-English documents and UI (i18n)

[Echo2f13]

Description

Enable NeuroForge to work with documents in multiple languages and generate content in the user's preferred language.

Features

• Process documents in: Spanish, French, German, Chinese, Japanese, Hindi, Arabic, etc.
• Generate quizzes/flashcards in the document's language
• UI translation (i18n) for interface elements
• Language auto-detection for uploaded documents
• Cross-language features (e.g., English UI, Spanish content)
• Translation of generated content to different language (optional)

Technical Considerations

Multilingual Embeddings

• Current: all-MiniLM-L6-v2 (English-focused)
• Upgrade to: multilingual-e5-large or paraphrase-multilingual-MiniLM-L12-v2

LLM Language Support

• Groq/OpenRouter models support multiple languages
• May need language-specific prompts
• Quality varies by language - need testing

Frontend i18n

• Use next-intl or react-i18next
• Extract all strings to translation files
• Support RTL languages (Arabic, Hebrew)

Acceptance Criteria

• Documents in non-English languages process correctly
• Content generated in same language as source
• UI supports at least 5 languages
• Language selector in settings
• RTL layout support

Priority

Low (Future)

Languages to Support (Phase 1)

1. English (default)
2. Spanish
3. French
4. German
5. Chinese (Simplified)