c6d8d1a973
- quizzes_create_question, update_question, delete_question and
reorder_questions on /api/v1/quizzes/{slug}/questions
- update_question replaces answers by id (kept, created, deleted), so
answer ids stored in past attempts stay valid; foreign ids are refused
- classes.CheckQuestion holds the importer's per-question rules, shared
with the manage routes; attempt scores are never touched (D-16)