- scrollReveal lands at the document bottom (window.scrollTo) instead of
scrollIntoView({ block: 'end' }): the old alignment sat above the
in-flow composer, so every Enter hopped the page up by the
composer+footer height and pushed the composer below the fold.
- The thinking window's pin state is now captured BEFORE the re-render
(const pinned = block.open && isThinkingNearBottom(textEl)): the
post-render distance read the new chunk's rendered height, not the
user's position, so any chunk taller than the 32px band (real-model
deltas, '\n\n' paragraph breaks) killed the follow at the first
2-newline gap.
- Mock LLM: new 'think in paragraphs' trigger (scratchpad with real
blank-line breaks, 60-char frames) — the 12-char mock frames never
rendered past the band, which is why the bug survived the E2E gates.
- E2E (both verified red against the old code):
test_submit_does_not_hop_up, test_thinking_window_follows_across_paragraph_breaks.
- Unit source-marker tests updated to the new contracts.