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/WriterTestSupport.swift

@@ -161,6 +161,13 @@ extension WriterFixture {
         try item(".trash/\(id)", "---\nschema: 1\ntitle: \(title)\norder: \(order)\n---\n\n")
     }
 
+    /// A **lane** written straight into `<root>/.trash/` — the opaque unit (03-board-ui.md § Trash),
+    /// where `kind: lane` is the only thing that tells it from a card in the flat container.
+    @discardableResult
+    func trashedLane(_ id: String, order: String, title: String) throws -> URL {
+        try item(".trash/\(id)", "---\nschema: 1\ntitle: \(title)\norder: \(order)\nkind: lane\n---\n\n")
+    }
+
     /// The board as the loader reads it right now — the value a reload would have landed.
     func snapshot() throws -> BoardModel {
         try BoardLoader.load(boardRoot: root).model