Makes a single section live by setting published_at, and cascade-publishes its lessons individually so per-lesson side effects fire. The response is the canonical section resource. If section or lesson validation fails, the entire request returns 422 without changing any publish timestamps. Pass an optional future published_at to schedule it; omit it to publish now. A past published_at is rejected. This is the default publish (auto_enroll: false) — to also grant existing enrollees access and notify them, use createCoursesSectionsPublishActions with auto_enroll instead. The root section cannot be published directly.
See Publishing in the Courses Skill for the publish paths.