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

KanbanTests/StyleModelTests.swift

@@ -109,7 +109,7 @@ struct StyleEditorSessionTests {
         let store = try BoardStore(rootURL: fixture.root)
         store.transient.beginStyleEditor(for: .items([card1, card2]))
 
-        try fixture.item("\(Ident.lane1)/\(Ident.card2)", tombstoned(order: "2048", title: "Second"))
+        try fixture.move("\(Ident.lane1)/\(Ident.card2)", toTrash: Ident.card2)
         await reload(store)
 
         let session = try #require(store.transient.styleEditor)
@@ -126,7 +126,7 @@ struct StyleEditorSessionTests {
         let store = try BoardStore(rootURL: fixture.root)
         store.transient.beginStyleEditor(for: .items([card3]))
 
-        try fixture.item(Ident.lane2, tombstoned(order: "2048", title: "Doing"))
+        try FileManager.default.removeItem(at: fixture.url(Ident.lane2))
         await reload(store)
 
         // The card's own flag never changed — its lane's did. Effective liveness is ancestor-walked,
@@ -141,7 +141,7 @@ struct StyleEditorSessionTests {
         let store = try BoardStore(rootURL: fixture.root)
         store.transient.beginStyleEditor(for: .items([card1]))
 
-        try fixture.item("\(Ident.lane1)/\(Ident.card1)", tombstoned(order: "1024", title: "First"))
+        try fixture.move("\(Ident.lane1)/\(Ident.card1)", toTrash: Ident.card1)
         await reload(store)
 
         #expect(store.transient.styleEditor?.target != .board)
@@ -155,8 +155,8 @@ struct StyleEditorSessionTests {
         let store = try BoardStore(rootURL: fixture.root)
         store.transient.beginStyleEditor(for: .board)
 
-        try fixture.item(Ident.lane1, tombstoned(order: "1024", title: "Todo"))
-        try fixture.item(Ident.lane2, tombstoned(order: "2048", title: "Doing"))
+        try FileManager.default.removeItem(at: fixture.url(Ident.lane1))
+        try FileManager.default.removeItem(at: fixture.url(Ident.lane2))
         await reload(store)
 
         #expect(store.transient.styleEditor?.target == .board)