Datepickers on native time.Time / lagoon.Date fields, file uploads on
materials, readings and class sessions managed from the course form
(course_id made nullable).
Seven admin controllers in a "Studia BM" navigation group, guarded by
jz.bm.access_courses, jz.bm.access_schedule and jz.bm.access_materials,
with Polish and English labels. Date and time fields are checked by the
models before a save and answered as 422 on the field.
Courses, meetings, class sessions, deadlines, readings with per-user
progress, materials with tags and file attachments. Timestamps are
stored in UTC and held as Europe/Warsaw text so the admin text inputs
can write them.
