SwiftUI's .onDrag(_:preview:) exposes no anchor or grab-point API and
lays the preview centered over the grabbed view, so a full-height lane
replica grabbed by its ~1.5-line title bar hung half a lane above the
pointer. DragPreviewAnchor is the pure fix: transparent one-sided
padding computed so the padded image's center IS the replica's title
bar - the system's centering then lands the bar under the cursor and
the body over the lane it was lifted from. LaneView measures the real
bar height in the geometry observer it already runs, accounting for the
accent band when the lane's color resolves.
Pixel-exact grab preservation would need re-homing the whole gesture
stack onto an AppKit beginDraggingSession path; declined for a polish
card - this gets the cursor onto the grabbed bar under either of
SwiftUI's possible placement rules. Manual verification pending (no
display here): grab specific bar pixels, colored + uncolored lanes,
large text sizes, multi-lane fan, cross-board drop geometry.
9 tests. 1661 green on both schemes with the paired card-width fix.
Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY
