fix: render consultation replies and typed tool activity

tests/unit/teacher-discussion-state.test.ts

@@ -304,6 +304,22 @@ describe('applying completed teacher replies', () => {
     expect(turn.discussionSnapshot).toBeUndefined();
   });
 
+  it('retains the original failed answer for inspection without changing the discussion', () => {
+    const owner = topic(flow, 'paused');
+    const before = structuredClone(owner.discussion);
+    const turn = request(owner);
+    const raw = '{"reply":"收到，先看看项目。","tool":{"kind":"flow",';
+    applyDiscussionReply(owner, turn, raw);
+    expect(turn.response).toBe('收到，先看看项目。');
+    expect(turn.unparsedResponse).toBe(raw);
+    expect(owner.discussion).toEqual(before);
+    const plainTurn = request(owner);
+    applyDiscussionReply(owner, plainTurn, '[项目说明](https://example.com)');
+    expect(plainTurn.discussionError).toBeUndefined();
+    expect(plainTurn.unparsedResponse).toBeUndefined();
+    expect(owner.discussion).toEqual(before);
+  });
+
   it('keeps legacy text as a normal answer without creating a component', () => {
     const owner = topic();
     const turn = request(owner);