🌍 Add Multi-Language Support

[Carrington-dev]

Description

Prepare book for translation into multiple languages.

Tasks

• Set up Sphinx i18n
• Extract translatable strings
• Create translation workflow
• Set up Crowdin or similar
• Create language selection
• Priority languages:
  • Spanish
  • French
  • German
  • Chinese
  • Portuguese
  • Japanese
• Create translation guide
• Set up automated builds per language

Files to Create

• docs/locales/
• TRANSLATION_GUIDE.md