fix: reliable shuffle-on-swap + per-Tonie volume multiplier - #67

Shuffle on swap:
- Remember the last Tonie per box across the empty phase (lift A off,
  put B on); previously the swap was practically never detected.
- Ignore stale poll placements for ICI boxes (caused wrong/double
  shuffles), persist the last placement, skip Tonies moved to another
  box, dedupe in-flight shuffles.
- Shuffling always yields a different chapter order.

Volume multiplier (new, per Creative/Content Tonie and Disc):
- While the Tonie is on the box, max volume and current loudness are
  raised by the factor; removing/replacing it restores the exact
  previous values.
- Max is changed first; the level is set only after the box applied it
  (the level is relative to max and the box rescales it on max change),
  then verified and re-sent if needed.
- Active boost state is persisted, so the undo survives restarts.

Max box/headphone volume adjustable in 1 % steps (1-100).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>