feat: 任务列表显示 turn_id 与 root_turn_id

host.py dispatch 打印补 turn_id/root_turn_id；执行器解析（local/Docker）透传；worker 写回 tasks 新列（新值非空才覆盖）；server 迁移与接口字段；控制台任务列表新增 turn/root turn 两列（短显+悬停全文）；新单测 9 个。

cloud/worker.py

@@ -607,7 +607,12 @@ class Worker:
                 "plan": "INTEGER",
                 "forked_from": "TEXT",
                 "environment_id": "TEXT",
-                "resume_message": "TEXT"}.items():
+                "resume_message": "TEXT",
+                # 任务列表显示 turn 用：本任务最近一轮产出过
+                # turn_id 的回合编号（local/Docker 两路都经
+                # _result_from_runner/_parse_host_result 提取）。
+                "turn_id": "TEXT",
+                "root_turn_id": "TEXT"}.items():
             if name not in cols:
                 try:
                     conn.execute(
@@ -640,8 +645,15 @@ class Worker:
     def _write_execution_result(self, task_id, result_text=None,
                                 error_text=None, actual_model=None,
                                 started_at=None, finished_at=None,
-                                child_pid=None):
-        """把执行结果写进 tasks 新列；老库缺列时先迁移再写。"""
+                                child_pid=None, turn_id=None,
+                                root_turn_id=None):
+        """把执行结果写进 tasks 新列；老库缺列时先迁移再写。
+
+        turn_id/root_turn_id 只在新值非空时覆盖：某轮没产出
+        turn（如提前失败门、解析不到 JSON）时保留上一轮的值，
+        列表里始终显示最近一个真实回合的编号，而不是被空值
+        洗掉。
+        """
         conn = _db_connect(self.db_path)
         try:
             self._ensure_result_columns(conn)
@@ -649,20 +661,27 @@ class Worker:
                 conn.execute(
                     "UPDATE tasks SET result_text = ?, error_text = ?,"
                     " actual_model = ?, started_at = ?, finished_at = ?,"
+                    " turn_id = COALESCE(?, turn_id),"
+                    " root_turn_id = COALESCE(?, root_turn_id),"
                     " updated_at = ? WHERE id = ?",
                     ((result_text or "")[:4000] if result_text else None,
                      (error_text or "")[:4000] if error_text else None,
                      actual_model, started_at, finished_at,
+                     turn_id, root_turn_id,
                      time.time(), task_id),
                 )
             else:
                 conn.execute(
                     "UPDATE tasks SET result_text = ?, error_text = ?,"
                     " actual_model = ?, started_at = ?, finished_at = ?,"
-                    " child_pid = ?, updated_at = ? WHERE id = ?",
+                    " child_pid = ?,"
+                    " turn_id = COALESCE(?, turn_id),"
+                    " root_turn_id = COALESCE(?, root_turn_id),"
+                    " updated_at = ? WHERE id = ?",
                     ((result_text or "")[:4000] if result_text else None,
                      (error_text or "")[:4000] if error_text else None,
                      actual_model, started_at, finished_at, child_pid,
+                     turn_id, root_turn_id,
                      time.time(), task_id),
                 )
             conn.commit()
@@ -2330,7 +2349,9 @@ class Worker:
             self._write_execution_result(
                 task_id, result_text=(result or {}).get("stdout", ""),
                 error_text="cancelled", actual_model=actual_model,
-                started_at=started_at, finished_at=time.time())
+                started_at=started_at, finished_at=time.time(),
+                turn_id=(result or {}).get("turn_id"),
+                root_turn_id=(result or {}).get("root_turn_id"))
             log_event(self.logger, "worker_cancelled", task_id=task_id,
                       project_id=task["project_id"], status="interrupted")
             return {"dispatched": True, "task_id": task_id,
@@ -2397,7 +2418,9 @@ class Worker:
         self._write_execution_result(
             task_id, result_text=stdout, error_text=error,
             actual_model=actual_model, started_at=started_at,
-            finished_at=finished_at)
+            finished_at=finished_at,
+            turn_id=(result or {}).get("turn_id"),
+            root_turn_id=(result or {}).get("root_turn_id"))
         # 附件暂存清理：任务终局后删 bundle 目录（重试走已存在
         # 续跑，文件已在 worktree 里，不再需要暂存）。
         self._cleanup_task_seed(task)