A 55-year-old male presents with epigastric pain 12 hours post-alcohol consumption, followed by vomiting fresh red blood (hematemesis) of 200ml. Physical exam: soft abdomen, tenderness in the upper abdomen, liver not palpable, spleen palpable 1.5 cm below the costal margin, normal blood pressure (BP). Bleeding persists despite initial management. Which of the following is the first-line intervention?