F4 SLICE-5: host E2E (propose/accept/reject/persist/stale/coexist) + seam fix: event-level net-effect matching survives host word-diff splitting (INV-9) (#12)

The accept E2E exposed a latent F3 limitation: VS Code word-diffs one
applied WorkspaceEdit into several minimal hunks when old/new share
interior tokens, so the registry's per-hunk exact match missed and seam
edits fell through as fragmented human spans. PendingEditRegistry.match
is replaced by matchEvent (all hunks inside the registered full range +
equal net delta — one applyEdit is one change event). Plan AMENDMENT 1.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

test/pendingEdits.test.ts

@@ -8,26 +8,53 @@ const AGENT: Provenance = {
 };
 
 describe("PendingEditRegistry (INV-9)", () => {
-  it("matches and consumes an exact registration", () => {
+  it("matches and consumes a single-hunk event equal to the 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" });
+    reg.register({
+      docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT, turnId: "t1",
+      full: { start: 3, end: 7, newLength: 3 },
+    });
+    const hit = reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 3 }]);
     expect(hit?.turnId).toBe("t1");
-    expect(reg.match("d.md", { start: 3, end: 7, text: "new" })).toBeNull();
+    expect(reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 3 }])).toBeNull();
   });
-  it("does not match a different doc, range, or text (human typing stays human)", () => {
+  it("matches a HOST-SPLIT event: several hunks inside the full range with the same net delta", () => {
+    // The host word-diffs one applied replace into multiple minimal hunks
+    // (observed on F4 accept) — per-hunk equality misses; net-effect matches.
+    const reg = new PendingEditRegistry();
+    reg.register({
+      docPath: "d.md", start: 10, end: 50, newText: "x".repeat(45), provenance: AGENT, turnId: "t2",
+      full: { start: 10, end: 50, newLength: 45 },
+    });
+    const hit = reg.matchEvent("d.md", [
+      { start: 12, end: 20, newLength: 9 },
+      { start: 25, end: 30, newLength: 6 },
+      { start: 40, end: 48, newLength: 11 },
+    ]);
+    expect(hit?.turnId).toBe("t2");
+  });
+  it("does not match a different doc, hunks outside the full range, or a different delta", () => {
+    const reg = new PendingEditRegistry();
+    reg.register({
+      docPath: "d.md", start: 3, end: 7, newText: "new", provenance: AGENT,
+      full: { start: 3, end: 7, newLength: 3 },
+    });
+    expect(reg.matchEvent("other.md", [{ start: 3, end: 7, newLength: 3 }])).toBeNull();
+    expect(reg.matchEvent("d.md", [{ start: 3, end: 8, newLength: 4 }])).toBeNull();
+    expect(reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 4 }])).toBeNull();
+    expect(reg.matchEvent("d.md", [])).toBeNull();
+  });
+  it("falls back to the minimized range when no full extent was registered", () => {
     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();
+    expect(reg.matchEvent("d.md", [{ start: 3, end: 7, newLength: 3 }])).not.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();
+    expect(reg.matchEvent("d.md", [{ start: 0, end: 0, newLength: 1 }])).toBeNull();
   });
   it("unregister reports whether the registration was still pending", () => {
     const reg = new PendingEditRegistry();
@@ -35,7 +62,7 @@ describe("PendingEditRegistry (INV-9)", () => {
     reg.register(p);
     expect(reg.unregister(p)).toBe(true);
     reg.register(p);
-    reg.match("d.md", { start: 0, end: 0, text: "x" });
+    reg.matchEvent("d.md", [{ start: 0, end: 0, newLength: 1 }]);
     expect(reg.unregister(p)).toBe(false);
   });
 });