automated testing for quick, low-friction python uv installation

[rodrigosf672]

Thank you for the QA Notes, @isabelizimm. Creating an issue for automated testing for similar process to which you have outlined in the notes. cc @midleman @testlabauto

QA Notes

@:win @:web

Be brave! Uninstall all non-System Pythons. For uv, it looks like this

uv cache clean
rm -r "$(uv python dir)"
rm -r "$(uv tool dir)"
rm ~/.local/bin/uv ~/.local/bin/uvx  

• Go to the Select Interpreter dropdown. You should see an option to install Python with uv.
• Select the option to install Python with uv. The quickpick should show ONLY supported Python versions (3.9-3.14), in the MAJOR.MINOR format
• Choose your Python version. This should install uv and then the chosen Python.
• If you are in a workspace, next, you have the option to create a venv. If you are not in a workspace, you should not be asked if you want to make a venv since we won't know where to place it.
• If creating a venv, it should be created and automatically selected in the Console.
• In venv/non-venv case, you should see your new Python (and maybe your new venv) in the interpreter dropdown.
• Once you have this new Python, you should no longer see the option to install Python in the interpreter dropdown

For automated testing purposes, we can force the "Install Python" option to always be shown in the "Select Interpreter" dropdown with the setting python.INTERNAL_alwaysShowUvInstallOption equal to True.

Originally posted by @rodrigosf672 in #12904 (comment)

[rodrigosf672]

Some implementation notes:

• part of the test should be (maybe) installing uv and then running uv sync?
• check if first step is necessary (experiment with and without it)
• tests run in alphabetical order, so consider naming this test as A... or Z... to let it be first or last (or alternative?)
• if the test fails, then all the ones after that would be broken, so maybe this would be best as last.
• OR do not use docker image at all, and have a separate workflow that runs on a nightly basis, so that we don't need to change anything. this would be justifiable due to the importance of this workflow for new users and students.
• nightly is fine since most folks using this are likely running actual releases and not dailies.