If I understand your question, it's a lot simpler than that. (Simpler as in not that functional.) It represents the directory structure as cascading menus.

I edit using VS Code and it provides help with linking from one document to another, including navigating to the file and even linking second level ('##') headings. MkDocs can report broken links when it builds the site.

Collaboration could be through sharing a Git repo. Perhaps other other ways I can't think of at this moment. Any way you could collaborate editing text files should work.