Let a section be any short alphanumeric label, and publish the ones in use

[vikrantwiz02]

Sections were fixed to the six letters A–F in three separate places, so an office that wants A1, CS2 or a numbered stream had nowhere to record it:

• Student.section — a two-character column carrying an A–F choice list
• assign_section — refused anything that was not one or two letters
• the Add / Edit Course Instructor dropdowns — the six letters written out literally

Change

A section is now any label of up to eight letters or digits. The choice list is gone, Student.section and CourseInstructor.section_label are both eight characters wide, and the assignment endpoint enforces the same limit:

assigned	result
A1	accepted
CS2	accepted
toolongsection	400 section must be up to 8 letters or digits.
B@	400 section must be up to 8 letters or digits.

Where the list comes from

Sections exist because one was assigned, so there is nothing to enumerate them from. A new endpoint gathers the labels actually in use — from students holding one and from offerings teaching one — and orders them so plain letters lead and numbered variants follow:

GET /aims/api/section/in-use/   →  {"sections": ["A", "B", "C", "D", "E", "F"]}

after assigning CS2 to a couple of students:

{"sections": ["A", "B", "C", "CS2", "D", "E", "F"]}

The frontend counterpart (FusionIIIT/Fusion-client#297) reads that list in the course-instructor dropdowns, so a section invented on the assignment screen shows up there with no further work.

Worth knowing

The Submit Grades section picker deliberately still lists sections from CourseInstructor offerings rather than this endpoint: its roster is scoped by offering, and listing a section nobody teaches would let a professor open a roster that cannot resolve.

Two migrations, both applied and checked locally: academic_information/0009, programme_curriculum/0053. manage.py check clean, no pending migrations.