A 58-year-old Indian man presents with a 4-month history of progressive dysphagia to solids, early satiety, and a 6 kg weight loss. He denies vomiting or haematemesis. On examination, he is cachectic with a palpable epigastric mass. Upper endoscopy reveals a 5 cm ulcerated lesion in the gastric antrum with rolled edges; biopsies confirm adenocarcinoma. CT staging shows no distant metastases, but there is thickening of the gastric wall with involvement of perigastric lymph nodes (N2). The tumour does not involve the pylorus or extend into the duodenum. What is the most appropriate surgical management?