make distability opt-in (#12885)
We have been claiming in our releases that we provide
archives/installers for uv-build, but we only upload it as a wheel to
pypi. This is because cargo-dist tries to be helpful and find all your
apps, but this scales poorly to large workspaces like ours, as stuff
like this slips in. So invert the default and make uv the only package
dist will see until we say otherwise.
See e.g. https://github.com/astral-sh/uv/releases/tag/0.6.14
Fixes #12883
