canEditComponent answers "is there content to type", and a heading is not
content — so the blocks with no editor of their own are now selectable too, and
get the heading alone.
The live draft writes into [data-block] when there is one. A titled component
renders as a wrapper, and writing into the wrapper would replace the heading with
the paragraph as somebody typed.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
