Sending a message now parks that message near the top of the viewport
and streams the reply into reserved end space below it, instead of
jumping to the bottom and chasing it.
- swap @tanstack/react-virtual for @legendapp/list in the chat timeline; the
streaming tail becomes a normal list row rather than a separately rendered
block, so one component owns the scroll position
- add timelineScrollAnchoring: pure anchored-turn geometry plus the three
scroll modes (following-end / anchoring-new-turn / free-scrolling)
- replace useChatAutoFollow with useChatTimelineScroll, which opts out of
automatic movement on real gestures via a generation counter instead of the
timer windows the old implementation needed to recognise its own writes
- move the load-older button, question/permission cards, recap, status row and
bottom spacer into the list header/footer, since the list owns its container
- extract useScrollShadow so the shadows can attach to that container
maintainScrollAtEnd and maintainVisibleContentPosition replace the manual
prepend anchor-hold and the mobile quiet-window prepend deferral.
Validated: workspace type-check, lint, web build, ui tests per file.
Scroll behaviour itself is unverified and needs manual testing on web, desktop
and iOS.
Bohdan Triapitsyn
d2d8669564