A 45-year-old woman with a BMI of 28 kg/m² complains of intermittent right upper quadrant (RUQ) pain, particularly after fatty meals. The pain is colicky and can last for a few hours. There is no jaundice or fever. An ultrasound scan reveals multiple gallstones within the gallbladder, with a normal common bile duct diameter and no gallbladder wall thickening. What is the most appropriate management?