A 27-year-old man is seen with a history of chronic sinus and pulmonary infections. He works as a salesperson in a retail outlet and denies any specific occupational exposure. He lives with his wife of 4 years and has no children. Family and travel history is noncontributory. On examination, he is in no acute distress. Lung exam reveals crackles in both lower lung zones and extremities show no clubbing. CXR is shown below.The most likely diagnosis is