Adds a dedicated drag HANDLE (grip) in the reorder gutter with the queue's drag gesture (6px threshold, absolute-position - root.y correction, three end paths incl. the changed-pressed safety net), so the row-body drag-to-sidebar stays intact. PlaylistView keeps component-local reorder state (slot math folds in the ListView viewport-y), a drop indicator and a floating ghost; commit fires PlaylistActions.reorder-track(from,to). Rust reuses the arbitrary-index persist path (repo::reorder for local, persist_custom for Qobuz) the arrows already back. Edge auto-scroll during drag is a follow-up TODO. Resolves#589.
cc
vicrodh
2103bbd3eb