Batch actions, clickable metadata, playback, auth launcher, action forms and
the glass warmup drive UI flows, so they belong with the controllers. Files
with more than three importers (or an importer that must stay untouched) keep
a one-line re-export at the old path.
The empty lyrics page offers Search online, which asks the enabled lyrics
providers in their configured order. The result is shown in the player
only and never written to the file; a late result is dropped after the
track changes, and a miss says so.
Port LRC, enhanced LRC, and TTML parsing plus ID3v2.3 lyrics writing and picture encoding. Keep legacy contracts and deep XML fallback; guard asynchronous player updates against stale track results.