A span that sizes to its children measures one, is told a length, and
hands that length back -- so whether measurement is idempotent decides
whether the two chase each other. Nothing checked it.
It holds: a wrapping text in a `Dir::RIGHT` span, which is the wrap axis
and the span's own axis together, stays at 881.84 across six repaints
that change nothing. So the narrowing recorded against LAYOUT.md §4 is
not something text does on its own, and looking for the cause there is
looking in the wrong place.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
