A 4-year-old girl from rural Maharashtra presents with a 3-month history of persistent cough, low-grade fever in the evenings, and failure to thrive. Her weight has plateaued for the past 4 months. On examination, she is thin, with mild hepatomegaly. Chest X-ray shows a right hilar opacity with a clear air bronchogram sign. Mantoux test (5 TU) is 18 mm induration at 48 hours. Sputum smear microscopy is negative. What is the most likely diagnosis?