Contributing refresh

[seddonym]

A big refresh of the local and ci tooling, most significantly switching to uv for managing packaging, and a justfile for commands.

[codspeed-hq]

CodSpeed Performance Report

Merging #252 will degrade performances by 17.65%

_{Comparing contributing-refresh (a389435) with main (b1c48c4)}

🎉 Hooray! pytest-codspeed just leveled up to 4.1.1!

A heads-up, this is a breaking change and it might affect your current performance baseline a bit. But here's the exciting part - it's packed with new, cool features and promises improved result stability 🥳!
Curious about what's new? Visit our releases page to delve into all the awesome details about this new version.

Summary

❌ 1 (👁 1) regression
✅ 22 untouched
⏩ 21 skipped¹

Benchmarks breakdown

	Mode	Benchmark	BASE	HEAD	Change
👁	Instrumentation	test_build_django_from_cache_a_few_misses[350]	678.5 ms	823.9 ms	-17.65%

Footnotes

1. 21 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩