A 58-year-old man with a known left inguinal hernia for 2 years presents to the emergency department with sudden onset severe left lower abdominal pain, vomiting, and abdominal distension for 6 hours. On examination, he is febrile (38.5°C), tachycardic (110/min), and has a tender, irreducible left inguinal swelling that is warm to touch and erythematous. Bowel sounds are absent. Plain abdominal X-ray shows multiple air-fluid levels and dilated small bowel loops. What is the most appropriate immediate management?