A 28-year-old man is brought to the emergency department 1 hour after sustaining a stab wound to the left lower abdomen (below the arcuate line, lateral to the rectus muscle). He is alert, blood pressure 118/76 mmHg, heart rate 92/min, respiratory rate 16/min. Abdominal examination reveals a 2 cm laceration with minimal blood oozing. There is mild tenderness around the wound but no peritoneal signs, guarding, or rigidity. What is the most appropriate next step in management?