v0.4.0

What's in this release

Added

• AI quiz generation (POST /api/quizzes/generate): generates questions from module content via Claude Haiku; output stays
  unpublished until educator reviews
• AI assignment feedback (POST /api/assignments/[id]/ai-feedback): rubric-aware feedback stored with full audit trail
• PII sanitisation layer strips emails and student IDs before every AI prompt
• AI audit columns on quizzes and submissions: aiModel, aiPromptHash, aiGeneratedAt/aiFeedbackAt
• MOCK_AI env flag (default true) — no live API calls without an explicit ANTHROPIC_API_KEY
• Vitest infrastructure: vitest.config.ts, shared DB seed/clean helpers, session factories
• 59 tests across 9 files covering quiz scoring, role helpers, PII sanitisation, enrollment, assignment submission/grading, quiz
  attempt, AI generation, and 503 fallback paths

Changed

• BREAKING: Enrollment is now admin/registrar-driven only — student self-enrollment removed from API, SSO access-control, and UI
• enrollments table gains enrolledBy and sectionId columns reflecting the ERP model