The schedule showed a lecturer only where the session notes named one
(Globalizacja), so the student plan had nobody under the other courses.
The session JSON now carries the course lecturer in its course ref and an
optional per-session lecturer (new nullable column, admin field, seed key)
for courses shared between two people. The student app shows the
session's own lecturer or, failing that, the course's.
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.
