[FEATURE] Multilingual LLM Support — Internationalization and localization

[gelluisaac]

Description

Add comprehensive multilingual support for LLM features including automatic
translation, locale-specific prompts, and multi-language RAG.

Scope

Build i18n infrastructure for global LLM deployment.

Files to Touch/Create

• astroml/llm/i18n/__init__.py
• astroml/llm/i18n/translator.py — Translation service
• astroml/llm/i18n/localizer.py — Content localization
• astroml/llm/i18n/prompts/ — Translated prompt templates
• astroml/llm/i18n/detector.py — Language detection
• astroml/llm/i18n/validators.py — Locale-specific validation
• api/middleware/i18n.py — Locale detection middleware
• locales/ — Translation files

Supported Languages

• English (primary)
• Spanish, French, German, Portuguese
• Chinese (Simplified/Traditional)
• Japanese, Korean
• Arabic, Hindi

Implementation Details

• Automatic language detection from user input
• Translated system prompts per locale
• RAG index per language (or multilingual index)
• Locale-specific evaluation datasets
• Fallback to English for unsupported languages
• Translation caching

Acceptance Criteria

• Supports 10+ languages
• Language detection accuracy >95%
• Translation latency <200ms
• Quality within 10% of English baseline
• RAG retrieval works per language
• Prompts culturally appropriate

Translation Strategy

• Prompt templates: professional translation
• Dynamic content: real-time translation via LLM
• Mixed queries: detect and route appropriately

Labels

enhancement, llm, i18n, user-facing