Fix local vs. DevContainer Poetry package conflicts

[hkeeler]

Per @lchen-2101 on #63 (comment)

Also making a note that devcontainer and native poetry doesn't seem to play nice together. When I ran the code in my local terminal outside of devcontainer, poetry shell wasn't working properly until I did a poetry install to get all the dependencies sync'ed up again; but that seems to break the dependencies for the devcontainer which then requires a poetry install in the vs code shell running in devcontainer.

I suspect this is related to a COPY in the Dockerfile and/or a volume mount where the Mac installed Python packages are not compatible with Linux Python...and vise-versa. Let's get to the root of the problem, and see how to make the two setups play nice. While we're at it, let's check in with each of our devs to make sure we're still getting value out of the DevContainer setup.