An audit found the fix from earlier tonight reintroduced through a
second button. A tap never resolves on the UP edge — the recogniser
returns None and the tap lands when the 300 ms multi-tap window closes
on a later tick, up to about 1.3 s after the press — so a single shared
latch had to survive that whole gap, and any other button's DOWN edge
inside it overwrote the answer.
Concretely: power wakes a dark phone, the volume rocker under the same
grip gets nudged within the second, and the pending power tap resolves
as "the panel was lit" and blanks the screen. That is exactly the
regression 8c7567e was written to fix.
`buttons` is already keyed per button so they cannot interfere; this
latch had reintroduced the coupling one level up. The test fails without
the fix — checked by reverting it.
133daa94ef