Similar to our semantics for packages with pre-release versions.
We will not use prerelease versions unless there are only prerelease
versions available, a specific version is requested,
or the prerelease version is found in a reasonable source (active
environment, explicit path, etc. but not `PATH`).
For example, `uv python install 3.13 && uv run python --version` will no
longer use `3.13.0rc2` unless that is the only Python version available,
`--python 3.13` is used, or that's the Python version that is present in
`.venv`.
f22e5ef69a