Switch environment manager to uv

[michplunkett]

Describe your changes

Switch environment managers from poetry to uv.

Checklist before requesting a review

• The code runs successfully.

michaelp@MacBook-Air-18 python-project-template % make test
uv run pytest -vs tests/
========= test session starts =========
platform darwin -- Python 3.12.0, pytest-8.3.4, pluggy-1.5.0 -- /Users/michaelp/Documents/GitHub/python-project-template/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/michaelp/Documents/GitHub/python-project-template
configfile: pyproject.toml
collected 1 item

tests/test_example.py::test_example PASSED

========= 1 passed in 0.00s =========
michaelp@MacBook-Air-18 python-project-template % make run
uv run python -m project
oh, what up?
michaelp@MacBook-Air-18 python-project-template %