Add multilingual feature

Add support for managing and displaying book content in multiple languages.

Functionality

• Enable/disable multilingual support for a book
• Configure supported languages per book
• Store translated page titles
• Display content in different languages using translation macros
• Support for both versioned and unversioned pages
• Maintain translation inheritance through version chain

Technical Implementation

New Classes

BookVersions.Code.PageTitleTransaltionClass

• language (String, required) - Language code
• title (String) - Translated page title
• status (StaticList) - Translation status ("not_translated", "in_progress", "translated") {code}

 BookVersions.Code.MultilingualClass

• enabled (Boolean, required) - Enable/disable feature
• supportedLanguages (StaticList, multiple) - List of supported languages {code}

Document Structure

• New Languages space under each book containing configuration
• Translation objects stored on: WebHome for unversioned pages / Version-specific content pages for versioned pages
• Translation macro for managing content translations

MyBook
├── Page1 (versioned page)
│   ├── WebHome (redirect)
│   ├── v1.0/ (hidden)
│   │   ├── PageTitleTransaltionClass objects
│   │   └── Content with translation macros
│   └── v2.0/ (hidden)
│       ├── PageTitleTransaltionClass objects
│       └── Content with translation macros
├── UnversionedPage (unversioned page)
│   └── WebHome
│       ├── PageTitleTransaltionClass objects
│       └── Content with translation macros
├── Versions
├── Variants
├── Libraries
└── Languages
    └── WebHome
        └── MultilingualClass object  

New Templates

• Modified templates for versioned/unversioned pages to support multilingual content
• Templates should wrap content in translation macro for default language

Administration

• New administration section in Languages space
• Interface for enabling/disabling multilingual support
• Management of supported languages

Navigation

• Language selector in book navigation menu
• Visual indicators for untranslated content

Acceptance Criteria

• Can enable/disable multilingual support for a book
• Can configure supported languages
• Language selection persists during navigation
• Can add translated content using macros
• If translation is missing show warning message or an empty page
• Can add translated titles for pages
• Translation inheritance works through version chain

Additional Notes

• Translation objects should be migrated when switching between versioned/unversioned pages
• Titles will use translation objects when multilingual is enabled (default language may or may not use an object)
• Content translation is managed through macros