The fade restarted an animation id at each rest and wake, and gpui hands
that id to every descendant: the scrubber's drag, hover and focus handle
and the buttons' focus were rebuilt under it. The bar's opacity now reads
the time since the last change through motion::since_change. The stage
tracks focus even without key handlers, so a focused bar button keeps
the bar up. The player's tests move to their own file.
Theme tokens in light and dark with high contrast, a palette cross-fade,
motion curves and a damped spring, embedded Lucide icons with Inter and
JetBrains Mono, Icon, Button, IconButton, and a gallery that captures
its own window. Reviewed by codex gpt-6-astra (max): PASS in round 3.
ZacharyZhang-NY