A 15-yeаr-оld femаle presents with severаl mоnths оf vague abdominal pain, constipation, and generalized bone pain. She had a kidney stone diagnosed two months ago. Labs show a serum calcium of 12.4 mg/dL (normal 8.8–10.3) with an elevated parathyroid hormone (PTH) level, normal renal function, and normal vitamin D level. What is the most likely diagnosis?