A 52-year-old woman with cirrhosis (Child-Pugh Class C) is admitted with persistent hypoglycemia (42 mg/dL) and elevated blood lactate (6.8 mmol/L). Her ammonia is elevated at 180 µmol/L. Liver biopsy shows extensive fibrosis and hepatocellular necrosis. Which metabolic derangement best explains the concurrent hypoglycemia and elevated lactate in this patient?