A partial slide left the app scaled small until another pull brought it
back (DUMP-bugs 8). Every path anyone checked did call endPull, so the
hunt for the one that didn't was the wrong shape: while restoring is a
step, some path skips it. It is now a function of `dragging`.
Release gates on speed and length as one projected number instead of a
distance test with a flick promotion bolted on. That promotion had never
fired anyway — it read rail.tapSlop, which is undefined, so the test was
`travel >= undefined`. Every commit on this rail has been distance-only.
57208c886a