You can do either. Folders are packages, so if you had /modes, that would be a modes sub-package which could be included in the top level code with import.

Well in Go there are no makefiles, but there is a tool called "go". It can build stuff for you. It maintains an assumption that all *.go files within the same directory belong to the same package. So you can't actually store multiple packages in the same dir or span files of one package across multiple dirs and use the go tool at the same time. Since the go tool makes like really easier, I choose to obey its conventions. That's why all files are in the same dir.

And I can't just add "modes" and "view" packages, because there are parts in them which depend on core concepts, which leads me to another "core" package or something. And that's 3 packages already. When there's 3, there's 4. It's easier the way it is.