Every client (bench_client, transcript_client, desktop-app) refolded and
rebuilt the ~3,200-row widget tree from scratch per SSE event, which is
the streaming-phase cost the P0 benchmark gate would otherwise measure
against a Compose app that updates one row. iris::widget::List gains
replace_back (swap the last row's widget in place, keeping its slot so a
pinned list stays pinned) and clear (the full-rebuild fallback);
transcript_ui::TranscriptScreen::apply diffs the folded row lists and
picks the cheapest update -- unchanged, append, replace-the-last-row, or
(rare regroup) a full rebuild, counted. TextEditCtx::set_with_spans lets a
row's text and span list land together on a streamed update.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
irisandClaude Fable 5.1
b3b1d47dd6