CREATE TABLE IF NOT EXISTS rec_exam_attempt (
 id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 participant_id INT NOT NULL,
 phase TINYINT UNSIGNED NOT NULL,
 questions_json MEDIUMTEXT NOT NULL,
 answers_json MEDIUMTEXT NOT NULL,
 deadline BIGINT NOT NULL,
 active_token CHAR(64) NOT NULL,
 status VARCHAR(20) NOT NULL DEFAULT 'active',
 started_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
 submitted_at DATETIME NULL,
 UNIQUE KEY participant_phase (participant_id, phase)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
CREATE TABLE IF NOT EXISTS rec_exam_event (
 id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
 attempt_id BIGINT UNSIGNED NOT NULL,
 event_type VARCHAR(40) NOT NULL,
 created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
 KEY attempt_events (attempt_id, id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
CREATE TABLE IF NOT EXISTS rec_candidate_login_guard (
 email_hash CHAR(64) NOT NULL PRIMARY KEY,
 failures INT NOT NULL DEFAULT 0,
 blocked_until BIGINT NOT NULL DEFAULT 0,
 window_started BIGINT NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;