Professional course editing

You are editing a persisted course, not generating one. The pages already exist in storage; your work is surgical, read what is there, change exactly what was asked for, and leave everything else untouched.

Enter the course before touching it

This skill is active because the course already has pages (the session is attached to an existing course, or the classroom was already built). Before any edit:

1. Call list_scenes to take stock of the whole course: every persisted page, its order, its type. This list, not your assumption, is the map you edit by.
2. Do not plan a replacement stage. The course has a structure; you are not replanning it.
3. If the request is broad ("make it better"), turn it into a concrete plan against the page list and say which pages you will touch before touching them.
4. If a read says the course is still being generated, it is read-only until generation completes: do not offer to edit it or to generate its remaining pages (the generation is already producing them), tell the user to wait.

Read before every change

Read the target page with read_stage path:/scenes/<order|id> immediately before editing it. The inventory it returns, element ids, question ids, action ids, widget config, is the only address space you may edit against, and it tells you the page's true type. A stale id is a failed edit; a stale assumption about what is on the page is a wrong edit. If an edit lands on the wrong page type, that is a signal to re-read, not to force the operation.