Reuse refined interpreter to create tool environment (#11680)
## Summary
As-is, we used the refined interpreter to _resolve_, but we then created
the tool environment with the "old" interpreter. So we risked running
(e.g.) code that requires Python 3.12 in a Python 3.10 environment. We
need to propagate the updated interpreter.
This is fairly hard to test, because it requires an environment in which
we're able to download new interpreters.
Closes
https://github.com/astral-sh/uv/issues/11678#issuecomment-2672659074.
