Probably not what you are aiming for but for Linux this is a somewhat solved problems. The default DM, Gnome, has built-in color shift with a time schedule AFAIK. For Wayland and xorg there are also numerous other solutions that do a display-level redshift, I can recommend wl-sunset for Wayland.
robot wise, I'd recommend something they can program with a raspberry pi and python, if they have some light background in programming. I had a quick look on Amazon and I have no affiliations with these, but maybe look for something like this: https://www.amazon.co.uk/FREENOVE-Raspberry-Tracking-Avoidan...
note this one doesn't have either a raspberry pi nor any batteries. you might find a better one.
* https://wiki.ros.org/rosbuild
* https://docs.ros.org/en/jazzy/Tutorials/Beginner-Client-Libr...
* https://docs.ros.org/en/jazzy/How-To-Guides/Ament-CMake-Docu...
It doesn't feel like a joke anymore.
Don't use ROS2. The benefits just aren't worth it. It's great for school but it's terrible for production.
Using ROS is a great way to turn your project and business into a cautionary tale.
If you like your email in mutt, then you'll probably like your feeds in newsboat.
https://en.m.wikipedia.org/wiki/Inductively_coupled_plasma#A...