I had a similar question a while back around code reuse, and later I’ve experimented a bit in command_palette (using the info shared by @James_Britt above and other sources) so it could be able to execute functions exposed by other tools, you can see how far I got commented out at the end of the main.lua file and mostly inside the util.lua as the include function.
Can’t remember much about the details at this point and I’m not using lua outside of tools to retain such knowledge but I think I had a few issues with including files that relied on other files in their own folder structure and so on, I am not sure if I solved this or not.