Clarify poetry usage in Readme

[jordandsullivan]

In our README we advise users to install using poetry, but do not follow up by noting that you must either activate the newly created poetry environment or prepend poetry run in front of all commands you want to run in it.

Why call this out?
In my experience, most people in this field are far more used to pip install and the basic setuptools workflow, which installs in whatever environment you happen to be in and relies on the user to create the appropriate virtual environment. With pip, no additional steps are required between install and running a program using the newly installed library; however with poetry, the additional step is required.

[bachase]

Would it help to elevate

ucc/docs/source/contributing.rst

Lines 25 to 26 in 1c1b6f1

	For all of the following commands, either first run ``poetry shell`` to enable the poetry managed virtual environment,
	or prefix each command with ``poetry run``.

from the docs to the README?

Note that poetry is only recommended if you are looking to contribute or run benchmarks. For users of the library, they can use pip or any other compatible packaging tool to get ucc

[jordandsullivan]

We want to invite contribution as a major tenant of UCC so I think it's important to elevate how folks can do this.

Also, when I run poetry shell on my local machine it throws an error seeming indicate deprecation:

Looks like you're trying to use a Poetry command that is not available.

Since Poetry (2.0.0), the shell command is not installed by default. You can use,

  - the new env activate command (recommended); or
  - the shell plugin to install the shell command

Documentation: https://python-poetry.org/docs/managing-environments/#activating-the-environment

Note that the env activate command is not a direct replacement for shell command.

On the other hand, if we did switch to uv (#209) this particular issue would become moot.

[bachase]

Oh good catch. I didn't realize that shell was deprecated. I can take this issue to address for now and can keep in mind on a transition to uv