Show HN: thcon, a config-driven theme controller

It's not the first CLI tool that switches terminal, editor, and desktop themes, and it certainly won't be the last. This one (mine) focuses more on switching between dark and light variants of a theme than on theme hopping, and is able to support a different set of tools. Notably, KDE Plasma, GNOME Shell user themes, and the macOS global dark mode are all supported, which is pretty unique I guess?