A 52-year-old man from Delhi presents with a 3-year history of hypertension. He is currently on amlodipine 5 mg daily and has achieved a BP of 138/88 mmHg. His serum creatinine is 1.2 mg/dL, eGFR 65 mL/min/1.73m², and urine albumin-to-creatinine ratio (UACR) is 45 mg/g. He denies diabetes, but has a strong family history of premature coronary artery disease. Which agent should be added to his current regimen to provide cardio-renal protection?