A 26-year-old sexually active woman presents to the emergency department with sharp right upper quadrant (RUQ) pain that began three days ago. The pain is pleuritic, worsening with deep breaths and movement. She denies jaundice, nausea, or vomiting but reports fever, chills, lower abdominal discomfort, abnormal vaginal discharge, and dyspareunia (pain during intercourse) over the past two weeks. On examination: RUQ tenderness without rebound or guarding Mild lower abdominal tenderness Pelvic exam: Cervical motion tenderness (Chandelier sign) and purulent cervical discharge Laboratory findings: Elevated C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) Normal liver function tests (LFTs) What is the most common causative organism of this disorder?