Include base installation directory in uv run PATH (#9585)
## Summary
On Windows, non-virtual environments put the `python.exe` in the
top-level of the installation directory, rather than in `Scripts`. This
PR adds those paths to `PATH` in `uv run` and `uv tool run`.
Closes
https://github.com/astral-sh/uv/issues/9574#issuecomment-2512217110.
