Add command to check if the lock file is up to date with the project metadata

[zanieb]

e.g. as in poetry check --lock (not yet sure why they deprecated poetry lock --check)

[zanieb]

Some discussion about the poetry lock --check change at https://github.com/python-poetry/poetry/pull/8015 and https://github.com/python-poetry/poetry/issues/6756

We ought to have a top-level uv check command eventually too but should it do this? I guess uv check --locked is an option?