The stack comes out — Kanban/Git/ deleted wholesale, ten thousand lines into history

Step 5 of strategy/01-git-excision.md: the seventeen dead engine files and the five remaining git test suites go (InertGitTests stays — the naming footgun is a Storage keeper). Two rescues ride ahead of the delete: HarvestedReceipt relocates to EchoLedger (the harvest surface outlives its git consumer; foundation for the deferred journal), and commentTimestamps joins the narrator it always served. The provider-swap purge test re-expresses over a git-free fake; the duplicate-id ladder keeps every pure historyRank pin and loses only the two ranker-driven ones. Resurrection point: tag pre-git-excision. 2,707 tests green.

Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy

KanbanTests/CardSessionUndoTests.swift

@@ -16,6 +16,25 @@ import Testing
 /// The fine steps' own round trips are `UndoWriteTests`' and `CommentWriteTests`'; the provider
 /// grammar is `HistoryProviderTests`'.
 
+// MARK: - A substrate that keeps no steps
+
+/// **A provider that retires every step on arrival** — the minimal fake `HistoryProviding.backedContent`'s
+/// own doc names ("a substrate that keeps no steps... and a test fake's"). `register(_:)` runs the
+/// step's retirement immediately and keeps nothing, which is what makes "purge rides the close flush"
+/// true over such a substrate with no tier check anywhere in the call path.
+@MainActor
+private final class NoBackingHistoryProvider: HistoryProviding {
+    var canUndo = false
+    var canRedo = false
+    var undoActionName: String?
+    var redoActionName: String?
+
+    func register(_ step: HistoryStep) { step.retirement?.run() }
+    func undo() {}
+    func redo() {}
+    func clear() {}
+}
+
 // MARK: - The window under test
 
 @MainActor
@@ -735,7 +754,7 @@ struct CardSessionPurgeTests {
         defer { fixture.tearDown() }
         let (window, card) = try await closedWithADeletedComment(fixture)
 
-        // `AppModel`'s teardown, and the add-git swap, both do exactly this.
+        // `AppModel`'s teardown does exactly this.
         window.board.clear()
         #expect(try fixture.entryNames("\(card)/comments/.trash").isEmpty)
     }
@@ -823,10 +842,11 @@ struct CardSessionPurgeTests {
         try fixture.item(path, commentText())
         let window = try makeWindow(fixture)
         window.comments.reload()
-        // The git provider drops every registration (its substrate is the commit trail) and retires
-        // it on the way past — which is what makes "purge rides the close flush" true on Pro with no
-        // tier check at any call site. Bound directly here: `register` reads no repository.
-        window.store.history = GitHistoryProvider(boardRoot: fixture.root)
+        // A substrate that keeps no steps drops every registration and retires it on the way past —
+        // which is what makes "purge rides the close flush" true structurally, with no tier check at
+        // any call site. `history` is weak, so the fake is held locally for the assertion's duration.
+        let noBackingProvider = NoBackingHistoryProvider()
+        window.store.history = noBackingProvider
 
         window.comments.delete(ItemID(rawValue: CommentIdent.one))
         await window.session.endSession()