Replaces the up/down arrow buttons on each track card with a grip
handle. Dragging a card shows a red insertion indicator on the target
card's top or bottom edge and drops it into the closest slot on
release, including gaps between cards or past the last card.
The card is only marked draggable while the grip handle is being held,
so text selection and button clicks inside the card body behave
normally. Existing promote_track_id logic (secondary at position 1
becomes primary on save) is unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
e0aa6e4817