Lanes delete into the trash — rendering, grammar, drag, clipboard, a11y

Phase 2 completes the lanes-in-trash card. TrashEntry merges the
trash's two kinds by rank in exactly ONE place (ItemPath.resolve's
own merge deleted in favor of it — the three-merge-points finding
shrinks instead of growing). TrashLaneRowView renders the opaque
row — tertiary plate, level-default lane glyph never the lane's own
icon, title + card count, no accents, no expansion; the column badge
counts rendered rows. Selection grammar: kind-homogeneous trash
selections — ranges skip the other kind, ⇧-extension stops at the
kind boundary, plain arrows walk the merged order, marquee stays
card-only (now load-bearing: rows register frames for arrows),
Select All card-scoped; successor-on-purge crosses kinds like
navigation as the interim for open Gap 7b5cbc90. Drag: TrashDrop
accepts lane sessions (drop on shown trash deletes), restoreLanes
routes a trash-sourced strip drop as an arrival-ranked within-board
move with an undo step. Clipboard: ⌘X/⌘V lane restore via opaque
lane subjects; fixed boardRoot(ofLaneFolder:) returning .trash as
the root — a same-board restore looked like an import and would
have reminted the lane it was restoring (pinned by test). A11y:
row = one flattened "title, deleted lane, N cards" element with
Delete/Reveal actions; BoardDiff crossings read lanes as
deleted/restored, shown-trash churn digested at row level. Agent
guide stays v7 — the literal already teaches lanes-trash-by-move
and kind stamping; drift-guard pins those lines. README trash
paragraph notes lanes.

Both schemes 1893 tests / 322 suites green.

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

KanbanTests/DragSessionTests.swift

@@ -188,10 +188,19 @@ struct TrashDropTests {
         #expect(accepts(operation: .move))
     }
 
-    /// "Lanes are not deliverable this way (a lane drag proposes only lane slots)."
-    @Test("A lane drag never proposes into the trash")
-    func lanesAreNotDeliverable() {
-        #expect(!accepts(kind: .lanes))
+    /// "Dropping a live card — **or lane** — on the shown trash deletes it … a lane drag over the
+    /// shown trash proposes the delete alongside its strip slots" (04-interactions.md ▸ The trash,
+    /// lanes extended 2026-07-29, retiring "a lane drag proposes only lane slots").
+    @Test("A live lane drag proposes the delete too — and no session proposes nothing")
+    func lanesAreDeliverable() {
+        #expect(accepts(kind: .lanes))
+        // Every other clause binds the lane exactly as it binds the card: a trashed row dragged out
+        // is not deletable back into the place it already is, a foreign board's lane is refused, and
+        // a hidden column takes nothing.
+        #expect(!accepts(kind: .lanes, container: .trash))
+        #expect(!accepts(kind: .lanes, isWithinBoard: false))
+        #expect(!accepts(kind: .lanes, isTrashShown: false))
+        #expect(!accepts(kind: .lanes, acceptsMutations: false))
         // And no session at all is no proposal either — the column is inert between drags.
         #expect(!accepts(kind: nil))
     }
@@ -451,8 +460,11 @@ struct DropSettleTests {
         #expect(session.hiddenMembers(onBoardRooted: store.rootURL) == [Self.card1, Self.card2])
     }
 
-    @Test("A lane session never proposes into the trash")
-    func laneSessionsHaveNoTrashLanding() throws {
+    /// The column draws the delete gesture's shadow for a **lane** session too (lanes extended
+    /// 2026-07-29): the accessor asks "is this proposal mine", and the kind question belongs to
+    /// `TrashDrop.accepts`, which is asked at hover and again at release.
+    @Test("A lane session's trash proposal reaches the column, and only on its own board")
+    func laneSessionsProposeIntoTheTrash() throws {
         let fixture = try makeBoard()
         defer { fixture.tearDown() }
         let store = try BoardStore(rootURL: fixture.root)
@@ -465,7 +477,10 @@ struct DropSettleTests {
         )
         session.propose(DropTarget(boardRoot: store.rootURL, container: .trash, index: 0))
 
-        #expect(session.trashProposal(onBoardRooted: store.rootURL) == nil)
+        #expect(session.trashProposal(onBoardRooted: store.rootURL) == 0)
+        #expect(session.shadowCount == 1)
+        // Another board's column draws nothing, like every other proposal accessor.
+        #expect(session.trashProposal(onBoardRooted: URL(filePath: "/tmp/other-board")) == nil)
     }
 
     // MARK: The hand-off