The overview loader was only active once missionControlOpen was already
true, so nothing existed during the pull and ZoneOverview.progress
following the rail was dead mid-drag. The cards appeared at release and
animated on their own clock — two motions, which is the seam TASK-60's
acceptance names.
missionPeek gates presentation only: visibility, mask, which body the
loader builds. Focus, dismissal and every commit path still read
missionControlOpen, so a preview draws and decides nothing. Masked to a
zero-size item while peeking so the in-flight gesture stays the rail's.
Dwell rather than any pull, so a flick to home never flashes the blur,
and it drops above the multitasking detent so the preview never shows a
destination the release would not commit.