add new tool git-status and support for --require-clean-branch on filesystem server

[rednap]

Is your feature request related to a problem? Please describe.
one of the main concerns when using the filesystem server is untracked changes to files/directories. this feature allows us to ensure the files being changed are in a git repo with a clean branch before making changes.

Describe the solution you'd like
a new tool git-status that can check the working dir git status and return "clean" or "not clean" with a new flag --require-clean-branch. when set filesystem will require a clean git branch when making changes to files/dirs.

Describe alternatives you've considered
Alternatives right now: don't prompt it to do work unless you've manually checked the dir/repo status first. not great. i could ensure it's only working in git repos now with a more fine-tuned configuration. ie: allow access to less directories, but nothing prevents changes to files not yet committed.

Additional context
this would be gold.