A 32-year-old woman with PCOS and secondary infertility for 18 months presents with irregular cycles (45–60 days). BMI is 28 kg/m². Basal FSH is 6 IU/L, LH is 18 IU/L (LH:FSH ratio 3:1), and free testosterone is elevated. She has not conceived after 6 months of clomiphene citrate 100 mg daily (days 3–7) with documented ovulation on ultrasound. What is the most appropriate next step in management?