Standalone UserControl combining Description + Steps into one card with
a top-right toggle. Description view shows raw editor or composed
MarkdownView (title + description + open steps). Steps view has an
add-step input and subtask rows with inline editing and check circles.
Adds Icon.Text geometry to IslandStyles for the steps→description toggle.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
