Ikhyeon-Cho/FastDEM ? reverse-engineered prompt

Build me a fast elevation mapping system for a mobile robot that can take LiDAR or RGBD point clouds and turn them into a local or global terrain map in real time. I want the core to be a clean C++ library that works on CPU only and can run on embedded hardware, with ROS1 and ROS2 wrappers as optional extras so I can launch it in a robot stack or use it on its own.

It should support basic map setup, loading a config file, integrating scans with robot and sensor transforms, and a few useful post processing steps like uncertainty handling, raycasting, inpainting, and feature extraction. Make it feel practical for navigation and traversability work, and include simple example configs and a small demo or launch setup for both ROS versions. If you need to check current ROS or build details, look them up online while you work.