- Add scripts/process_rtk_gnss.py to convert WGS84 to ENU.

- Update global_optimizer.py to export initial SVD map and use RTK data by default.

- Refactor src/optimizer_modules for timing logging and robustness.

- Tune ICP and overlap thresholds.

Initial commit: Multi-stage LiDAR mapping fusion framework with SVD alignment and GTSAM optimization