F3 SLICE-3: pending-edit registry + sidecar section-merge update (INV-9 groundwork) (#6)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/pendingEdits.test.ts

@@ -0,0 +1,32 @@
+import { describe, it, expect } from "vitest";
+import { PendingEditRegistry } from "../src/pendingEdits";
+import type { Provenance } from "../src/model";
+
+const AGENT: Provenance = {
+  kind: "agent", id: "claude",
+  agent: { sdk: "@cline/sdk", model: "sonnet", sessionId: "run-1" },
+};
+
+describe("PendingEditRegistry (INV-9)", () => {
+  it("matches and consumes an exact registration", () => {
+    const reg = new PendingEditRegistry();
+    reg.register({ docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT, turnId: "t1" });
+    const hit = reg.match("d.md", { start: 3, end: 7, text: "new" });
+    expect(hit?.turnId).toBe("t1");
+    expect(reg.match("d.md", { start: 3, end: 7, text: "new" })).toBeNull();
+  });
+  it("does not match a different doc, range, or text (human typing stays human)", () => {
+    const reg = new PendingEditRegistry();
+    reg.register({ docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT });
+    expect(reg.match("other.md", { start: 3, end: 7, text: "new" })).toBeNull();
+    expect(reg.match("d.md", { start: 3, end: 8, text: "new" })).toBeNull();
+    expect(reg.match("d.md", { start: 3, end: 7, text: "neww" })).toBeNull();
+  });
+  it("unregister removes a failed application", () => {
+    const reg = new PendingEditRegistry();
+    const p = { docPath: "d.md", start: 0, end: 0, newText: "x", provenance: AGENT };
+    reg.register(p);
+    reg.unregister(p);
+    expect(reg.match("d.md", { start: 0, end: 0, text: "x" })).toBeNull();
+  });
+});