- Add markdown-basics module with lessons for headings, text formatting,
lists, links, and inline code
- Integrate markdown section with blue color theme (#5b8dd9)
- Add markdown mode support in CodeEditor and LessonEngine
- Add markdown preview rendering using marked library
- Add section overview page with educational content
- Add markdown reference page with syntax guide
- Add i18n translations for 6 languages (EN, DE, PL, ES, AR, UK)
- Update router to recognize #markdown as section route
- Add all section-specific CSS styles for markdown theme
- Add HTML mode support with new validation types (element_exists,
element_count, attribute_value, element_text, parent_child, sibling)
- Create 3 HTML lesson modules: Elements, Forms Basic, Forms Validation
- Implement side-by-side preview comparison (Your Output vs Expected)
- Add merge animation with "Perfect Match!" overlay on validation success
- Render expected output from solutionCode field in lesson JSON
- Update schema to support HTML mode and solutionCode
- Reorder modules: HTML first, then CSS, then Tailwind
- Update tests for new functionality
