Archive a course by its Edusign id: the course is locked (isArchived: true on the wire), so it leaves the active views and accepts no further edit or signature. This is the explicit v3 counterpart of GET /v1/course/lock/:courseId. The live-signing fields (Teams session, simple signature and its PIN) are cleared and the pending signature emails of its attendance states are reset, like a v1 lock; its scheduled reminders, start/end webhooks and absence push are cancelled asynchronously. No attendance sheet PDF is generated by this route.

An unknown id, or one belonging to another school, answers 404 COURSE_NOT_FOUND; a course that is already archived answers 409 COURSE_ALREADY_ARCHIVED. When the school setting "Do not archive attendance sheets when the trainer signature is missing" is on and no professor of the course has signed, the archive is refused with 409 COURSE_PROFESSOR_SIGNATURE_MISSING and nothing changes (one signature from any professor of the course is enough).

Fires the on_course_archived webhook ({ courseId }) once per successful archive, asynchronously, next to its deprecated twin on_course_locked; a delivery failure never changes this response.