A 34-year-old Indian woman presents with progressive swelling of the face, hands, and feet over 3 weeks. She reports foamy urine and weight gain of 8 kg. On examination: BP 128/82 mmHg, bilateral pitting ankle edema, ascites present. Laboratory findings: serum albumin 2.1 g/dL, total serum protein 4.8 g/dL, 24-hour urine protein 6.2 g, serum creatinine 0.9 mg/dL, fasting blood glucose 92 mg/dL. Lipid profile shows total cholesterol 385 mg/dL, triglycerides 420 mg/dL. Renal ultrasound is normal. What is the most likely diagnosis?