Back out the render-at-release drop presentation

The settle rule 3f4125e introduced — at release the shadow swaps for the
dropped card(s) drawn in place immediately — is withdrawn on review. The
board returns to the presentation the committed-overlay hold has always
had: the shadows keep standing at their landing slot and the originals
keep their lift until the echo reload lands, whatever the operation was,
and the real faces arrive with the snapshot that carries the write.

Gone with it: the DropLanding/DroppedItem seam and the three landing
accessors, the hold's landing/operation payload and the removesOriginals
and keepsIdentity halves it decided, the pickup-captured titles a
cross-board arrival's face needed, LaneSlot.dropped with DroppedFace and
DroppedCardFace, the strip's dropped-lane run, and the trash column's
settled tombstone rows — the same presentation at the delete gesture's
end, which goes for the same reason while the drop-to-delete write and
its shadow row stay exactly as they were.

Kept: the hold itself, which predates the commit, along with the 1500 ms
failed-write timeout, its injectable duration and its extracted expire,
and the guard that keeps a settled release past retargeting. The tests
pinning those stay; the ones asserting what the landing slot drew are
gone, and the suite now pins the hold's own claim — the arrangement does
not move at the release.

The pause between the release and the echo is therefore an open design
question again, filed on the Redesign board.

Claude-Session: https://claude.ai/code/session_01CqjXB7ASoWtbyoGod68k97

Kanban/UI/Board/DragShadow.swift

@@ -12,12 +12,6 @@ import SwiftUI
 /// **Hit-transparent, always.** The strip's own drop target has to stay live beneath the shadows
 /// (DRAG-REORDER.md § Single-target dispatch: "shadow placeholders are hit-transparent, so the strip
 /// target stays live beneath them"), and a shadow that swallowed the release would strand the drop.
-///
-/// **A drag's shadow lives exactly as long as the drag does.** The moment the mouse comes up the
-/// slot it was holding draws the dropped card itself (`LaneView`'s `runSlots`, `DroppedCardFace`) —
-/// "a lingering shadow over a hidden card is the hold failing its one job" (03-board-ui.md § Motion,
-/// sharpened 2026-07-28). The one shadow that outlives a release is the cross-board *lane* arrival's,
-/// which has no column to draw until the echo lands (`BoardView.runSlots`).
 struct DragShadow: View {
 
     /// Matched to the surface it stands in for — a lane's plate is 10, a card's is 8.