{"message":"🎯 Ai Là Triệu Phú — API","status":"success","version":"2.0.0","time":"2026-04-05T23:27:19.753Z","endpoints":{"health":"GET    /health","play":"GET    /api/questions/play","check":"POST   /api/questions/check       { question_id, answer_index }","list":"GET    /api/questions?tier=1&page=1&limit=20&search=keyword","stats":"GET    /api/questions/stats","getOne":"GET    /api/questions/:id","create":"POST   /api/questions              { difficulty_tier, content, option_a..d, correct_option_index }","update":"PUT    /api/questions/:id           { ...partial fields }","delete":"DELETE /api/questions/:id"}}