Materialize the trash — store, undo, and the container universe

Phase 2 swaps every consumer: Liveness and its ancestor walk are gone,
replaced by ItemContainer — a UUID set plus the container side it
lives on, presence the whole test, one selection boundary instead of
the old liveness law. Deletion stages by place: board cards move to
the trash at a store-minted head rank, trash-side delete is permanent
behind its confirmation, Delete Immediately skips the trash from
anywhere, lane delete captures the subtree and removes the folder.
Restore has no method at all — moveCards resolves members in either
container, so drag-out and cut-paste are the ordinary moves 13 calls
them, registering ordinary Move steps. The delete inverse moves the
card back to its captured lane and rank; redo replays the captured
trash rank, a value the gesture actually wrote; lane undo recreates
the subtree byte-faithfully in session. Purges register nothing —
where 13's trash section contradicts its own Rules on that, Rules
wins, filed for ruling. Staleness collapsed to present-or-absent: a
container is a path, so a foreign restore fails the delete step's
expectation structurally. Legacy tombstones migrate on the loose-file
tail hook, cards oldest-first so minting above top reproduces the
retired newest-first column, lanes returning live, one folded loss
row naming both directions. Put Back, restoreByDrag,
receiveRestoredCards, TrashEntry, and the kind machinery are deleted;
the trash column renders the container correctly with its full face
rework left to phase 3.

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

Kanban/UI/Board/SelectionClicks.swift

@@ -47,24 +47,25 @@ struct MarqueeControl {
     ///   loop simply keeps declining for the rest of that drag. Deciding this by frames rather than
     ///   by gesture priority is what keeps the two from fighting, and it stays correct as the
     ///   masonry reflows.
-    /// - **The side is fixed at the origin** — 04-interactions.md ▸ The trash's rule, stored in the
-    ///   session so a band dragged across the boundary keeps its meaning.
+    /// - **The container is fixed at the origin** — 04-interactions.md ▸ The trash's rule ("the
+    ///   rubber band stays on the side it started on"), stored in the session so a band dragged
+    ///   across the boundary keeps its meaning.
     /// - **Live-updating, not commit-on-release**: each sample recomputes the whole set from the
     ///   band, so the selection follows the cursor both ways. An empty band clears rather than
     ///   leaving the last non-empty one standing.
     /// - **Alive under the read-only lock**: selection is not a mutation (02-architecture.md § The
     ///   lock's scope), and no `isEditingInline` guard either — a click-away mid-rename already
     ///   commits through the field's own focus loss.
-    func gesture(side: Liveness) -> some Gesture {
+    func gesture(in container: ItemContainer) -> some Gesture {
         DragGesture(minimumDistance: MarqueeSession.minimumDistance, coordinateSpace: .named(BoardView.stripSpace))
             .onChanged { value in
                 if !session.isActive {
                     guard !registry.contains(value.startLocation) else { return }
-                    session.begin(at: value.startLocation, side: side)
+                    session.begin(at: value.startLocation, in: container)
                 }
                 session.update(to: value.location)
                 guard let rect = session.rect else { return }
-                let ids = MarqueeMath.selection(rect: rect, targets: registry.all, side: session.side)
+                let ids = MarqueeMath.selection(rect: rect, targets: registry.all, in: session.container)
                 if ids.isEmpty {
                     store.clearSelection()
                 } else {
@@ -74,7 +75,7 @@ struct MarqueeControl {
                     // Both are spelled out rather than defaulted, because `select`'s sole-member
                     // default would otherwise pick one up the moment a band happened to sweep
                     // exactly one card.
-                    store.select(ids, liveness: session.side, anchor: nil, head: nil)
+                    store.select(ids, in: session.container, anchor: nil, head: nil)
                 }
             }
             .onEnded { _ in session.end() }
@@ -111,7 +112,7 @@ extension View {
     func marqueeTarget(
         _ id: ItemID,
         kind: SelectionKind,
-        side: Liveness,
+        container: ItemContainer,
         in registry: MarqueeTargetRegistry
     ) -> some View {
         // The space name is read here, on the main actor, rather than inside the measuring closure:
@@ -120,7 +121,7 @@ extension View {
         return onGeometryChange(for: CGRect.self) { proxy in
             proxy.frame(in: .named(space))
         } action: { frame in
-            registry.update(MarqueeTarget(id: id, kind: kind, side: side, frame: frame))
+            registry.update(MarqueeTarget(id: id, kind: kind, container: container, frame: frame))
         }
         .onDisappear { registry.remove(id) }
     }