You can't really sandbox development dependencies in any meaningful way. I want to throw everything and the kitchen sink into one container per project, not install a specific version of Python, Node, Perl or what have you globally/namespaced/whatever. Currently there's no good solution to that problem, save perhaps for a VM.
uv doesn't provide strong isolation; a package you install using uv can attempt to delete random files in your home folder when you import it, for example.
