CI: fail CI if lockfile is out of sync with project

[superlopuh]

We also want to automate the updating of the lockfile, but I think this also helps make sure that they're always in sync before merging, in case someone updates the dependency locally.

The version overloading is related to this issue in uv, which is that it doesn't have an official mechanism to support dynamic versions: astral-sh/uv#7533

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.74%. Comparing base (2a38956) to head (7414af2).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3639   +/-   ##
=======================================
  Coverage   90.74%   90.74%           
=======================================
  Files         465      465           
  Lines       58779    58779           
  Branches     5632     5632           
=======================================
  Hits        53340    53340           
  Misses       3997     3997           
  Partials     1442     1442           

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