Synced LRC highlights the playing line, keeps it centred and seeks on click.
Plain text scrolls continuously with a nudge knob instead — a highlight on
guessed timings turns guaranteed drift into what looks like a bug. Seuraa
kappaletta turns following off without losing the highlight, and scrolling by
hand turns it off too.
Fixes the scroll landing in the wrong place (offsetTop measured from a
different coordinate space than the box it was applied to) and the fader
shifting the deck sideways at score 100 (auto-sized grid columns plus a
readout spanning both).
