-- Seed integrity --
  ok  all 412 subjects imported
  ok  102 aviation-marked subjects
  ok  (+) markers stripped from names
  ok  diploma duration corrected to 3 years (6 semesters)
  ok  engineering = 5 years
  ok  no subject sits beyond its programme length
-- Sheet building --
  ok  odd semester → term 1, even → term 2
  ok  semester 5 curriculum fully copied (7 subjects)
  ok  re-load is idempotent
  ok  sheet keeps snapshotted credits after curriculum edit
-- Remove / add --
  ok  course without grades removable
  ok  S6 subject added into S5 sheet
  ok  removal blocked once grades exist
-- Lock respected --
  ok  sheet load blocked after submission
  ok  add blocked after submission

15 passed, 0 failed