Decision: Confirm cohort-owned curriculum for the first consolidation release

[alexeygrigorev]

Normative decision: Open decision 3

Decision needed

Confirm that reusable Course owns family identity while the evolved Cohort keeps separate homework, questions, projects, criteria, settings, submissions, scores, and certificates. Add complete cohort duplication and defer versioned reusable curriculum.

Non-goals

Do not introduce CurriculumVersion or deduplicate historical definitions during the migration-critical path.

Acceptance criteria

• Owner accepts the recommendation or specifies a replacement ownership/versioning model.
• Duplication semantics and historical isolation are explicit.
• Course migration and workflow issues reflect the decision.

Validation scenarios

Duplicate a cohort, edit the copy's assignment/rubric, and prove the original and historical learner records do not change.

Dependencies

Blocks Course→Cohort model work under #5.