A 38-year-old man from Delhi presents to the emergency department with acute left-sided flank pain radiating to the groin, nausea, and haematuria. Non-contrast CT (NCCT) abdomen confirms a 6 mm left ureteric stone at the pelvic brim with mild hydronephrosis. Serum creatinine is 1.0 mg/dL, and urine culture is sterile. Vital signs are stable, pain is controlled with NSAIDs. What is the most appropriate next step in management?