Comparison of ANI Between Preoperative and Postoperative Ultrasound-guided TAP Block in Laparoscopic Cholecystectomy

The goal of this clinical trial is to learn if the timing of ultrasound-guided transversus abdominis plane block (US-TAP block) administration (preoperative vs. postoperative) affects the perioperative analgesia nociception index (ANI) in adult patients undergoing laparoscopic cholecystectomy. The main questions it aims to answer are: * Does the timing of the US-TAP block significantly influence intraoperative ANI values? * Does the difference in US-TAP block timing and subsequent ANI values correlate with actual patient recovery, postoperative pain scores (VAS), and complication rates? If there is a comparison group: Researchers will compare the experimental group (Group A: US-TAP block before surgical incision) to the control group (Group B: US-TAP block after wound closure) to see if early block administration provides superior intraoperative pain suppression and reduces postoperative pain or analgesic consumption. Participants will: * Undergo standard general anesthesia induction and maintenance. * Receive a bilateral US-TAP block with a total of 30 mL of 0.2% ropivacaine, administered either before incision (Group A) or after closure (Group B). * Be monitored via standard monitoring devices alongside an ANI monitor. * Use an intravenous patient-controlled analgesia (IV-PCA) pump for 24 hours after surgery. * Participate in postoperative assessments to measure pain scores (VAS), rescue analgesic consumption, satisfaction, and complications at specific intervals up to 24 hours post-surgery.