6. Add `POST /api/v1/admin/courses/:id/modules/:moduleId/quizzes/generate` endpoint

[DeFiVC]

What: Add an admin endpoint that generates quizzes for a specific module using the AI service.

Why: Admins need to generate quizzes through the admin API without going through the user-facing endpoint. This allows bulk quiz generation and management.

Scope: Create endpoint that calls the AI service to generate questions for a specific module. Store the generated quiz. Return the generated quiz with questions (including correct answers for admin review).

Acceptance criteria:

• Admin can generate quizzes via admin API
• Generated quiz includes correct answers
• Quiz is stored in the database
• Generation is logged in audit logs

Technical context: src/modules/quizzes/quiz.service.ts:28-147 — generateQuiz. src/modules/quizzes/ai-client.ts — AI service client.

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