fix(web): isolate rectification answers from tool-step planning text

Mastra intermediate text-delta was published as answer.delta, then set-focus domain errors reset the attempt and replayed evidence. Publish only the terminal no-tool step, persist the next probe on the server, and ground batch quotes in the source turn.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/tests/rectification-step-answer.test.ts

@@ -0,0 +1,53 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import {
+  applyStepAnswerChunk,
+  createStepAnswerState,
+  flushStepAnswerOnStreamFinish,
+  shouldPublishStepText,
+} from "../src/lib/rectification-agentic/v9/step-answer.ts";
+import { mapStreamChunkToPhase, mapStreamChunkToThinking } from "../src/lib/rectification-agentic/v9/stream-mapping.ts";
+import { PUBLIC_RECTIFICATION_TOOLS } from "../src/lib/rectification-agentic/v9/public-receipt.ts";
+
+function isPublicTool(name: string): boolean {
+  return (PUBLIC_RECTIFICATION_TOOLS as readonly string[]).includes(name);
+}
+
+function chunk(type: string, payload?: Record<string, unknown>) {
+  return { type, payload };
+}
+
+test("does not publish intermediate tool-step text as answer.delta", () => {
+  const state = createStepAnswerState();
+  applyStepAnswerChunk(state, chunk("text-delta", { text: "Let me set" }), isPublicTool);
+  applyStepAnswerChunk(state, chunk("tool-call", { toolName: "rectification-record-evidence-batch" }), isPublicTool);
+  const afterTool = applyStepAnswerChunk(
+    state,
+    chunk("tool-result", { toolName: "rectification-record-evidence-batch" }),
+    isPublicTool,
+  );
+  assert.equal(afterTool.kind, "discard");
+  applyStepAnswerChunk(state, chunk("text-delta", { text: "记下了，2020年4月开始实习。" }), isPublicTool);
+  const finish = applyStepAnswerChunk(state, chunk("step-finish", { reason: "stop" }), isPublicTool);
+  assert.deepEqual(finish, { kind: "publish", pieces: ["记下了，2020年4月开始实习。"] });
+});
+
+test("never publishes reasoning-delta to the browser", () => {
+  assert.equal(mapStreamChunkToPhase(chunk("reasoning-delta", { text: "Let me" }) as never), null);
+  assert.equal(mapStreamChunkToPhase(chunk("text-delta", { text: "Let me" }) as never), null);
+  assert.ok(mapStreamChunkToThinking(chunk("reasoning-delta", { text: "先核对经历。" }) as never));
+});
+
+test("publishes only the terminal no-tool step as assistant text", () => {
+  const state = createStepAnswerState();
+  applyStepAnswerChunk(state, chunk("step-start"), isPublicTool);
+  applyStepAnswerChunk(state, chunk("text-delta", { text: "_probe" }), isPublicTool);
+  applyStepAnswerChunk(state, chunk("tool-call", { toolName: "rectification-compare-candidates" }), isPublicTool);
+  applyStepAnswerChunk(state, chunk("step-finish", { stepResult: { reason: "tool-calls" } }), isPublicTool);
+  assert.equal(shouldPublishStepText({ calledTool: true, text: "_probe" }, "tool-calls"), false);
+  applyStepAnswerChunk(state, chunk("step-start"), isPublicTool);
+  applyStepAnswerChunk(state, chunk("text-delta", { text: "已经记下实习。" }), isPublicTool);
+  const finish = flushStepAnswerOnStreamFinish(state, "stop");
+  assert.deepEqual(finish, { kind: "publish", pieces: ["已经记下实习。"] });
+});