A 52-year-old woman from Bangalore with a history of recurrent urinary tract infections presents with acute right flank pain and fever (38.5°C). NCCT abdomen shows a 9 mm right ureteric stone at the mid-ureter with moderate hydronephrosis. Urine culture is positive for E. coli. Serum creatinine is 1.8 mg/dL (baseline 1.0 mg/dL). What is the most appropriate immediate next step in management?