A 28-year-old man is brought to the emergency department 45 minutes after a motor vehicle collision. On examination, he is alert and oriented to person and place but not time (GCS 14/15). He has a 2 cm laceration over the left temporal region with mild bleeding. CT head (non-contrast) performed immediately shows no acute intracranial hemorrhage, no midline shift, and no skull fracture. Vitals are stable: BP 128/82 mmHg, HR 88/min, RR 16/min, SpO₂ 98% on room air. What is the most appropriate next step in management?