Guard the deinit detach by superview so a container whose render view
was stolen by a newer, not-yet-windowed container cannot rip the shared
view out of it. Narrow the loading-gate heal to .ready only: the old
video still playing during the details/streams fetch can emit .playing,
which would open the gate to stale time updates and break the
stale-error suppression in play()'s catch.
2ff248e262