The message engine outlives its substrate — harvested to Kanban/Changes/ as the change narrator

Step 2 of strategy/01-git-excision.md: CommitMessageEngine and the composer seam relocate to a neutral module renamed away from commit vocabulary (ChangeNarrator, ChangeNarrationRequest, ChangeNarrating, SemanticChangeNarration, ChangeAuthorship), GitChangedPath extracts from GitCommitOperation as ChangedPath, and the one git tie severs — authorship's foreign case carries a display name, not a GitIdentity. The spec tests transplant as ChangeNarratorTests, alive until the journal work begins. 3,009 tests green.

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

Kanban/Changes/ChangedPath.swift

@@ -0,0 +1,53 @@
+import Foundation
+
+// MARK: - Changed paths
+
+/// Harvested 2026-08-08 from `Kanban/Git/` per `strategy/01-git-excision.md`. This value type, and
+/// the narrator it feeds, are the designated core of the future activity feed / foreign-change
+/// journal — the "previous snapshot" input the narrator diffs against is supplied by the caller by
+/// contract; the journal will supply it from memory/snapshots, where the git stack supplied it from
+/// HEAD.
+
+/// One path found to differ between the last-recorded snapshot and the working tree (what `git
+/// status` reports, for the git-backed supplier).
+///
+/// Board-root-relative and file-granular, which is the unit both consumers want: staging adds or
+/// removes exactly these, and attribution asks a question per *file* (06 ▸ Interaction with external
+/// writers: "classify every observed change, per file").
+public struct ChangedPath: Sendable, Equatable, Hashable {
+
+    /// The path, relative to the board root, in git's own spelling (`/` separators, no leading dot).
+    public let path: String
+
+    /// Whether the file is **gone** from the working tree.
+    ///
+    /// The `modified-by` rule turns on this bit — "any true deletion in the window falls back to
+    /// `Lanework External` — a deletion leaves no file to stamp" — which is why the rename half
+    /// below is a separate fact rather than folded in here.
+    public let isDeletion: Bool
+
+    /// Whether this path is one end of a **rename** the provider paired up (libgit2's pairing, for
+    /// the git-backed supplier).
+    ///
+    /// "**A folder move is not a deletion**: items match by id across the whole board … so a moved
+    /// card attributes by its stamp like any changed file" (06). A paired departure is therefore a
+    /// deletion on disk that the window must not be demoted by.
+    public let isRename: Bool
+
+    /// Whether the path is **new in this commit** — surfaced rather than inferred (git's own
+    /// `GIT_DELTA_ADDED`, for the git-backed supplier, and a rename's arriving end).
+    ///
+    /// It exists for the comment verb family (01-storage-format.md § Enhanced schema): comments are
+    /// window-scoped and the board snapshot never carries them, so "Comment on 'X'" and "Edit comment
+    /// on 'X'" cannot be told apart by a diff of two snapshots — the only thing that distinguishes a
+    /// comment folder arriving from one being rewritten is whether HEAD already had it, which is
+    /// exactly the question this diff already answered.
+    public let isArrival: Bool
+
+    public init(path: String, isDeletion: Bool, isRename: Bool, isArrival: Bool = false) {
+        self.path = path
+        self.isDeletion = isDeletion
+        self.isRename = isRename
+        self.isArrival = isArrival
+    }
+}