D11. LESSON.md for simple blocks

Elabora is a superset of LESSON.md 1.9. Export and import map text, headings, notes, images, accordions/tabs and knowledge checks, and report every loss. Multiple-select checks use type: multiple-select, confirmed on 17 Oct 2026 in Slate’s format reference and v1.9 template. LESSON.md has no explicit licence: interoperability only, no reuse of Slate code.