mpv can pause or resume OUTSIDE PodTUI — system sleep/lock, AirPod
removal, device swap, OS media keys, the Now Playing center. The poll
previously only reflected commands PodTUI sent, so the UI stayed stuck
on "playing" (or "paused") with a frozen position clock.
The poll now reads mpv's live pause state each tick: an external pause
reconciles the UI to paused (persisting progress, syncing media
controls) while keeping the poll armed; an external resume brings the
UI back to playing. A paused player is polled at a throttled rate
(PAUSE_WATCH_TICKS) so the watch costs ~1 IPC read per second instead
of hammering mpv; a dead process (track end / crash) finalizes the
track.
