switch to uv

[maskarb]

• remove pipenv in favor of uv
• format via ruff instead of black
• move from setup.py to a pyproject.toml
• simplify tox.ini config

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 4 lines in your changes missing coverage. Please review.

Project coverage is 93.7%. Comparing base (48cbacc) to head (c88149f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #537   +/-   ##
=====================================
  Coverage   93.7%   93.7%           
=====================================
  Files         62      62           
  Lines       4646    4654    +8     
  Branches     644     645    +1     
=====================================
+ Hits        4351    4359    +8     
  Misses       158     158           
  Partials     137     137