Take the jvui that answers a pointer resting on a pill

The pin was at the merge, which is a rev before the hover work: jvui grew
c/overlay! after it — a deferred draw on a root frame of its own, clear of
every clip, with its size remembered so a card near an edge is moved rather
than clipped — and glimmer-jvui grew the crossing events, on-hover and
on-unhover once each, off the pass that paints.

That is what the reaction pills have been asking for all along: they have
sent :on-hover and hung `reactor-card` under themselves since they were
written, and no backend had ever answered.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>