Maintainer dual-gate (Codex) found the suppression could swallow a genuine
low-delta trackpad wheel scroll-up for ~1.4s after a render:
_recordNonMessageScrollIntent() only recorded message-pane wheel intent at
deltaY<-30, so a gentle deltaY:-5 left both intent helpers false and the
post-render branch returned before movedUp set _messageUserUnpinned.
- Track recent low-delta upward message-pane wheel intent separately
(_lastMessageWheelIntentMs / _recentMessageWheelIntent), recorded for any
upward wheel (deltaY<0). The decisive deltaY<-30 sticky-unpin is unchanged.
- Require !_recentMessageWheelIntent() before suppressing the artifact, so a
real gentle scroll-up inside the window still unpins.
- Add behavioral node-harness regressions: gentle wheel inside the window
unpins; no-intent artifact inside the window stays suppressed; outside the
window unpins. Plus a source lock that low-delta intent is tracked.