- Send Now Playing elapsed time once per 5-second bucket; the modulo check
fired for every frame of that second (12 updates/s on average).
- Skip mpv renders while paused unless mpv requests a redraw (seek, new
frame, PiP change, new load) instead of redrawing the same frame at
display rate.
- Read playback time untracked in the progress bar and time labels while
the controls are hidden, so they are not re-rendered on every tick.
- Only clear the current SponsorBlock segment when one is set.