A 52-year-old man from Delhi presents with a 6-week history of epigastric pain relieved by food and antacids. He reports black tarry stools for 2 days and mild dizziness. On examination, he is pale, heart rate 102/min, blood pressure 118/76 mmHg. Hemoglobin is 9.2 g/dL (baseline 14 g/dL). Upper endoscopy reveals a 1.5 cm ulcer in the duodenal bulb with a visible vessel at the base and adherent clot. He is H. pylori positive and takes no NSAIDs. What is the most appropriate immediate management?