uv init ignores workspace when --isolated flag is used

[j178]

Summary

Per #5250 (comment)

It would also be great to have an argument (perhaps leveraging the global isolated option) that allows us to disable workspace discovery when we don't want to add a project as a member.

Test Plan

$cargo run -- init work
$ cargo run -- init work/pkg-a --isolated
warning: `uv init` is experimental and may change without warning
Initialized project sub-c in /tmp/work

[zanieb]

Thanks! Can you add a test case?

[j178]

Sure!

[zanieb]

I'm going to have @charliermarsh take a look here — we're thinking about the future of the --isolated flag.

[charliermarsh]

I think this is fine for now, since it's consistent with uv run and we need to revisit this alongside that usage.