investigate: associate `uv`-managed projects & scripts with their associated python interpreter

[austin3dickey]

uv allows for the creation and management of "projects": https://docs.astral.sh/uv/guides/projects

If one of these projects exists already, and is opened in Positron, we could probably optimize the user experience by starting the Python interpreter that's associated. Are there other optimizations we could make?

In addition, uv has specific ways to manage dependencies of python scripts, which allow it to create venvs that are used during uv run. https://docs.astral.sh/uv/guides/scripts

Could we associate those interpreters with those scripts as well?

Depends on work in #3093, and relates to #5165 (but is distinct because this issue assumes the project exists already).

[austin3dickey]

Are there other optimizations we could make?

Had the thought that if the env doesn't exist yet (e.g. a project with a uv lockfile was freshly cloned from git) we could create it first. But that shouldn't be in the scope of this issue.