ability.yaml

每个 Ability 位于 abilities/<ability_id>/ability.yaml，声明自身信息和持有的 Node 清单。

id: guide_planning
name: Travel Guide Planning
description: Collect the trip brief and generate a day-by-day itinerary.
entry: collect_info
nodes:
  - id: collect_info
    name: Collect information
    description: Ask for destination, dates, budget and preferences.
  - id: generate_itinerary
    name: Generate itinerary
    description: Produce a day-by-day itinerary with sources and budget.

字段说明：

字段	说明
id	必须与目录名一致，项目内唯一
name / description	展示信息
entry	入口 Node id
nodes[]	该 Ability 持有的 Node；Node 目录必须存在于 nodes/<id>/

ability.md 描述如何选择和编排这些 Node。使用 ability list/switch/validate/delete 和 node 管理。