Method updatePosition

packages/server/src/services/task.service.ts:525–561

* 更新任务位置（用于拖拽排序） * 如果同时传了 status，会进行状态流转并通知前端

(id: string, position: number, status?: TaskStatus)

        description: true,
      },
    });

    if (!task) {
      throw new NotFoundError('Task', id);
    }

    const hasDescription = Boolean(task.description?.trim());
    const titlePreview = buildTextPreview(task.title, TASK_TITLE_MAX_LENGTH);
    const usesHistoricalTitleBody =
      !hasDescription
      && (task.title.length > TASK_HISTORICAL_TITLE_BODY_THRESHOLD || task.title !== titlePreview);
    const body = hasDescription
      ? task.description!
      : usesHistoricalTitleBody
        ? task.title
        : '';
    const prompt = hasDescription
      ? buildTaskPrompt(task)
      : usesHistoricalTitleBody
        ? task.title
        : task.title.trim();

    return {
      taskId: task.id,
      title: titlePreview,
      titlePreview,
      body,
      bodySource: hasDescription ? 'description' : usesHistoricalTitleBody ? 'historical_title' : 'none',
      prompt,
      isTruncated: task.title !== titlePreview,
    };
  }

  /**
   * 创建任务
   * - 校验项目存在
   * - 自动计算 position（同状态下最大 position + 1）
   */
  async create(projectId: string, input: CreateTaskInput) {
    const normalizedInput = normalizeCreateTaskInput(input);