iOS/Android fire pointercancel when the native pan claims a touch while the
touch stream keeps flowing. Treating it as gesture end either orphaned the
gesture (drag released mid-screen rested between columns until the next tap)
or armed the idle settle with the finger still down (slow scrolls at the edge
columns glitched and snapped back). Track the live touch sequence and ignore
pointercancel while it is active; touchend stays the real finger lift.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
1bda76d488