A 28-year-old woman from Mumbai presents with a 5-day history of progressive dyspnea, pleuritic chest pain, and fever (38.8°C). She has no significant past medical history but reports a boil on her left forearm that she squeezed 2 weeks ago. Chest X-ray shows multiple thin-walled cavitary lesions in both lungs with pneumothorax on the right. Blood culture grows Gram-positive cocci in clusters that are catalase-positive and coagulase-positive. Which virulence factor is most likely responsible for the pulmonary cavitation and pneumothorax?