A 66-year-old man presents with melaena and dizziness. He takes low-dose acetylsalicylic acid and naproxen for osteoarthritis. Blood pressure is 96/60 mm Hg, heart rate 108 beats/min, and haemoglobin is 78 g/L. After initial resuscitation with intravenous fluids, what transfusion threshold is recommended by Canadian gastrointestinal bleeding guidance for most stable patients without active massive haemorrhage?