feat: comments-first ask + comment→reply→offer→proposal loop (D19/D10/D8, PUC-8); sunset the input webview (spec §6.10)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/e2e/suite/threads.test.ts

@@ -41,6 +41,17 @@ async function getApi(): Promise<CowritingApi> {
   return api;
 }
 
+// Task 6 (D10): every human comment on a coedited doc now also fires the
+// respond-in-thread turn (createThreadOnSelection/reply). This suite predates
+// that loop and asserts exact message sequences unrelated to it — stub the
+// turn to reject so the loop runs harmlessly (no real @cline/sdk call, and no
+// extra machine message lands in the sidecar this suite's assertions read).
+function stubReplyLoop(api: CowritingApi): void {
+  api.threadController.setTurnRunnerForTest(async () => {
+    throw new Error("F2 suite: reply-loop turn stubbed off (not under test here)");
+  });
+}
+
 // Reaches the controller's internal docs map for reply/resolve handlers (which
 // expect a live vscode.CommentThread). Spec §6.8 "drive the ThreadController and
 // assert Comments-controller state" fallback.
@@ -67,6 +78,7 @@ suite("F2 region-anchored threads (host E2E)", () => {
   test("create on selection persists a thread sidecar", async () => {
     const doc = await openSample();
     const api = await getApi();
+    stubReplyLoop(api);
     const start = doc.getText().indexOf("quick brown fox");
     const editor = vscode.window.activeTextEditor!;
     editor.selection = new vscode.Selection(doc.positionAt(start), doc.positionAt(start + "quick brown fox".length));
@@ -89,6 +101,7 @@ suite("F2 region-anchored threads (host E2E)", () => {
 
   test("reply appends and resolve flips status, both persisted", async () => {
     const api = await getApi();
+    stubReplyLoop(api);
     const art0 = readSidecar();
     const threadId = art0.threads[0].id;