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。

host.py

@@ -214,6 +214,8 @@ def _summarize_trace_item(method, params):
     返回 [] 表示该通知不进链路（userMessage 等）。
     ts 取通知的 completedAtMs/startedAtMs（毫秒 epoch），
     没有时为 None，服务端展示时按无时间处理。
+    thread 取通知的 threadId（模型内子代理与主任务同文件时，
+    服务端凭它把条目归属到不同代理；没有时为 None，归主任务）。
     """
     item = (params or {}).get("item")
     if not isinstance(item, dict):
@@ -221,8 +223,11 @@ def _summarize_trace_item(method, params):
     item_type = item.get("type")
     item_id = item.get("id") or ""
     ts = params.get("completedAtMs") or params.get("startedAtMs")
+    thread = params.get("threadId")
+    if not thread and isinstance(params.get("thread"), dict):
+        thread = params["thread"].get("id")
     if item_type == "commandExecution":
-        return [{"kind": "exec", "id": item_id, "ts": ts,
+        return [{"kind": "exec", "id": item_id, "ts": ts, "thread": thread,
                  "command": (item.get("command") or "")[:500],
                  "cwd": item.get("cwd") or "",
                  "exitCode": item.get("exitCode"),
@@ -235,6 +240,7 @@ def _summarize_trace_item(method, params):
             path = ch.get("path") or ""
             entries.append({"kind": "file",
                             "id": item_id + ":" + path, "ts": ts,
+                            "thread": thread,
                             "path": path, "change": ch.get("kind") or "",
                             "status": item.get("status") or ""})
         return entries
@@ -242,32 +248,60 @@ def _summarize_trace_item(method, params):
         text = item.get("text") or ""
         if not text:
             return []
-        return [{"kind": "message", "id": item_id, "ts": ts,
+        return [{"kind": "message", "id": item_id, "ts": ts, "thread": thread,
                  "phase": item.get("phase") or "", "text": text[:300]}]
     if item_type == "reasoning":
         summary = item.get("summary") or item.get("content") or []
         text = " ".join(s for s in summary if isinstance(s, str)).strip()
         if not text:
             return []
-        return [{"kind": "reasoning", "id": item_id, "ts": ts,
+        return [{"kind": "reasoning", "id": item_id, "ts": ts, "thread": thread,
                  "summary": text[:200]}]
     if item_type == "mcpToolCall":
-        return [{"kind": "tool", "id": item_id, "ts": ts,
+        return [{"kind": "tool", "id": item_id, "ts": ts, "thread": thread,
                  "server": item.get("server") or "",
                  "tool": item.get("tool") or "",
                  "status": item.get("status") or ""}]
     if item_type == "functionCallOutput":
-        return [{"kind": "call", "id": item_id, "ts": ts,
+        return [{"kind": "call", "id": item_id, "ts": ts, "thread": thread,
                  "name": item.get("name") or ""}]
     if item_type == "plan":
         text = item.get("text") or ""
         if not text:
             return []
-        return [{"kind": "plan", "id": item_id, "ts": ts,
+        return [{"kind": "plan", "id": item_id, "ts": ts, "thread": thread,
                  "text": text[:300]}]
     return []
 
 
+def _trace_file_path(state_path, task_name):
+    """链路文件路径：state 文件同目录下的 host-traces/<清洗后名字>.jsonl。
+
+    与 Server.set_trace_file、cloud 的 _trace_file_name 同款清洗，
+    三边算出同一名字，delegate 的父链路标记才能落进父任务文件。
+    """
+    safe = re.sub(r"[^A-Za-z0-9_.-]", "-", str(task_name))
+    return os.path.join(
+        os.path.dirname(os.path.abspath(state_path)),
+        "host-traces", safe + ".jsonl")
+
+
+def _append_trace_marker(state_path, task_name, entry):
+    """往另一任务的链路文件追加一条标记（delegate 向父链路报到用）。
+
+    尽力而为：目录建不出、写失败都不影响回合本身。父链路的
+    行数上限由属主进程自己的计数器管，这里不重复计数（标记
+    一轮至多两条，超限风险可忽略）。
+    """
+    try:
+        path = _trace_file_path(state_path, task_name)
+        os.makedirs(os.path.dirname(path), exist_ok=True)
+        with open(path, "a", encoding="utf-8") as f:
+            f.write(json.dumps(entry, ensure_ascii=False) + "\n")
+    except Exception:
+        pass
+
+
 class Server:
     """单个 app-server 进程，多 thread 并发。"""
 
@@ -302,12 +336,8 @@ class Server:
         时 trace_path 保持 None，不影响回合。
         """
         try:
-            safe = re.sub(r"[^A-Za-z0-9_.-]", "-", str(task_name))
-            trace_dir = os.path.join(
-                os.path.dirname(os.path.abspath(state_path)),
-                "host-traces")
-            os.makedirs(trace_dir, exist_ok=True)
-            self.trace_path = os.path.join(trace_dir, safe + ".jsonl")
+            self.trace_path = _trace_file_path(state_path, task_name)
+            os.makedirs(os.path.dirname(self.trace_path), exist_ok=True)
             self._trace_lines = 0
         except Exception:
             self.trace_path = None
@@ -2566,11 +2596,26 @@ def main():
                    "created_at": time.time(), "turns": []}
             state["tasks"][args.name] = sub
             save_state(args.state, state)
+            # 子代理链路：向父任务链路文件报到（开始 + 结束各一条），
+            # 服务端凭标记把子链路文件拼进父任务的代理链；子任务自己
+            # 的过程条目仍写它自己的链路文件（main 起动时按 --name 定）。
+            child_trace = (os.path.basename(srv.trace_path)
+                           if srv.trace_path else None)
+            _append_trace_marker(
+                args.state, args.parent_task,
+                {"kind": "agent-start", "id": "agent:" + args.name,
+                 "name": args.name, "prompt": (args.task or "")[:300],
+                 "trace": child_trace, "ts": int(time.time() * 1000)})
             result = run_task_turn(srv, state, sub, args.task,
                                    args.model, args.effort, args.sandbox,
                                    timeout=args.turn_timeout,
                                    interrupt_file=_interrupt_request_path(args.state, args.name))
             save_state(args.state, state)
+            _append_trace_marker(
+                args.state, args.parent_task,
+                {"kind": "agent-done", "id": "agent:" + args.name + ":done",
+                 "name": args.name, "status": sub["status"],
+                 "trace": child_trace, "ts": int(time.time() * 1000)})
             print(json.dumps({"sub_task": args.name, "status": sub["status"],
                               "text": result.get("text", "")},
                              indent=2, ensure_ascii=False))