A 38-year-old woman with a history of laryngeal papillomatosis (recurrent respiratory papillomatosis, RRP) is scheduled for elective hysterectomy. Preoperative airway assessment reveals a Mallampati score of III, normal thyromental distance, and full neck extension. However, flexible laryngoscopy shows multiple papillomas obstructing 60% of the laryngeal inlet. Inhalational induction with sevoflurane is initiated. After loss of consciousness, the anesthesiologist attempts direct laryngoscopy but encounters significant obstruction and cannot visualize the vocal cords. Bag-mask ventilation is adequate. What is the most appropriate next step?