feat: 命令台子代理链路（主任务/模型子代理/委派子任务 + 过程调用实时同步）

host：链路条目带 thread 归属；delegate 向父链路文件写 agent-start/done 标记。服务端：GET /tasks/{id}/agents 聚合父链路 + 子链路文件成代理链（状态口径：委派以结束标记为准、无标记即进行中；模型子代理无结束信号时父任务运行中为进行中、否则未知）。命令台：新增子代理链路区，随 SSE 流防抖刷新；扁平链路也渲染 agent 标记。

cloud/tests/test_task_trace.py

@@ -173,6 +173,79 @@ class TaskTraceTestCase(unittest.TestCase):
         self.assertEqual(status, 401)
         self.assertEqual(events, [])
 
+    def test_agents_auth_and_not_found(self):
+        status, _ = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id)
+        self.assertEqual(status, 401)
+        status, _ = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.other_key)
+        self.assertEqual(status, 403)
+        status, _ = self._req(
+            "GET", "/tasks/nope/agents", key=self.owner_key)
+        self.assertEqual(status, 404)
+
+    def test_agents_chain_groups_calls_by_agent(self):
+        self._set_task(status="running")
+        self._write_trace([
+            json.dumps({"kind": "exec", "id": "c1", "thread": "th-main",
+                        "command": "make", "ts": 1000}),
+            json.dumps({"kind": "tool", "id": "t1", "thread": "th-sub",
+                        "server": "s", "tool": "read", "ts": 1001}),
+            json.dumps({"kind": "agent-start", "id": "agent:rev",
+                        "name": "rev", "prompt": "review code",
+                        "trace": "rev.jsonl", "ts": 1002}),
+            json.dumps({"kind": "agent-done", "id": "agent:rev:done",
+                        "name": "rev", "status": "completed",
+                        "trace": "rev.jsonl", "ts": 1004}),
+        ])
+        with open(os.path.join(self.trace_dir, "rev.jsonl"),
+                  "w", encoding="utf-8") as f:
+            f.write(json.dumps({"kind": "exec", "id": "c9",
+                                "command": "grep", "ts": 1003}) + "\n")
+        status, data = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.owner_key)
+        self.assertEqual(status, 200)
+        self.assertEqual(data["status"], "running")
+        by_kind = {a["kind"]: a for a in data["agents"]}
+        main = by_kind["main"]
+        self.assertEqual(main["status"], "running")
+        self.assertEqual([e["id"] for e in main["calls"]], ["c1"])
+        model = by_kind["model"]
+        self.assertEqual(model["status"], "running")
+        self.assertEqual([e["id"] for e in model["calls"]], ["t1"])
+        delegate = [a for a in data["agents"]
+                    if a["kind"] == "delegate"][0]
+        self.assertEqual(delegate["name"], "rev")
+        self.assertEqual(delegate["status"], "completed")
+        self.assertEqual(delegate["prompt"], "review code")
+        self.assertEqual([e["id"] for e in delegate["calls"]], ["c9"])
+        self.assertEqual(delegate["updated_ts"], 1004)
+
+    def test_agents_delegate_without_done_stays_running(self):
+        # 委派进程与父任务相互独立：父任务已结束、无结束标记时，
+        # 子任务仍算进行中（不能谎报它已中断）。
+        self._set_task(status="completed")
+        self._write_trace([
+            json.dumps({"kind": "agent-start", "id": "agent:rev",
+                        "name": "rev", "prompt": "review",
+                        "trace": "rev.jsonl", "ts": 1002}),
+        ])
+        status, data = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.owner_key)
+        self.assertEqual(status, 200)
+        delegate = [a for a in data["agents"]
+                    if a["kind"] == "delegate"][0]
+        self.assertEqual(delegate["status"], "running")
+        self.assertEqual(data["agents"][0]["status"], "completed")
+
+    def test_agents_missing_file_is_main_only(self):
+        status, data = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.owner_key)
+        self.assertEqual(status, 200)
+        self.assertEqual(len(data["agents"]), 1)
+        self.assertEqual(data["agents"][0]["kind"], "main")
+        self.assertEqual(data["agents"][0]["calls"], [])
+
 
 if __name__ == "__main__":
     unittest.main()