A 52-year-old man from Delhi presents with a 6-week history of progressive weakness, bleeding gums, and petechial rash on lower extremities. On examination, he has generalized lymphadenopathy, hepatomegaly, and multiple ecchymoses. Laboratory findings: hemoglobin 8.5 g/dL, WBC 85,000/μL (85% blasts), platelets 15,000/μL. Peripheral blood smear shows numerous large cells with abundant cytoplasm, prominent nucleoli, and Auer rods. What is the most likely diagnosis?