A 72-year-old woman from Delhi presents with a 2-month history of severe headache, scalp tenderness, and jaw claudication (pain while chewing). She also reports vision loss in the right eye for 3 days. On examination, the right temporal artery is tender, nodular, and non-pulsatile. ESR is 95 mm/h and CRP is 18 mg/dL. Temporal artery biopsy shows granulomatous inflammation with giant cells and fragmentation of the internal elastic lamina. What is the most likely diagnosis?