New reference lists: GET /api/v1/departments, GET /api/v1/contractors and GET /api/v1/course-catalog.
POST /api/v1/users accepts department_name and contractor_name instead of identifiers.
POST /api/v1/enrollments accepts employee_no and course_code instead of identifiers.
POST /api/v1/enrollments now applies course licences like the admin panel: 422 for a course licensed only inside
a learning path or with an expired licence, 409 SEAT_LIMIT_REACHED when a seat-based licence is full.
Stable public API host per product (https://api.elearning.edu.pl), independent of the data-centre node.
Public OpenAPI document at https://api.elearning.edu.pl/openapi.json.
Webhook delivery format renamed to platform.v1 (payload and signature unchanged; the previous name is still accepted
when creating or updating subscriptions).
