Add an html kind to the artifact generator: it renders a styled HTML report from
a stored JSON spec (title + heading/paragraph/list/table/code blocks), producing
text/html bytes the sidebar already previews inline in the sandboxed iframe,
while keeping the spec as the source of truth so edit and rewrite make real
versions. So a single artifact both renders inline and versions conversationally.
The renderer is a fixed program fed the spec as data, and every spec text value
is HTML-escaped into the output.
Alex
6c8a72c836