fix(chat): prevent stale timeline scroll and rerenders

- Disable LegendList end-maintenance that could snap after user scrolling
- Cancel stale imperative scrolls and release settled turn anchors
- Stabilize handoff run data to avoid per-event timeline rerenders
6d7b07fcb5Julius Marminge committed on 8/29/2026, 6:01:54 AMparentb86a1c6
4 files changedLine totals unavailable