Refresh CI setup.

[CathalMullan]

• Remove divan.
• Add slim Nix env for CI.
• Run tests only once (well, twice only for benchmarks).
• Ensure cancelling build stops Nix env
• Wipe GH cache, build from scratch

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #100 will create unknown performance changes

_{Comparing 99-consolidate-ci-tooling (23ceeeb) with main (69039b9)}

Summary

🆕 22 new benchmarks ⁉️ 22 (👁 22) dropped benchmarks

Benchmarks breakdown

	Benchmark	main	99-consolidate-ci-tooling	Change
🆕	matchit benchmarks/actix-router	N/A	181.1 µs	N/A
🆕	matchit benchmarks/gonzales	N/A	4.8 µs	N/A
🆕	matchit benchmarks/matchit	N/A	5.2 µs	N/A
🆕	matchit benchmarks/ntex-router	N/A	27.4 µs	N/A
🆕	matchit benchmarks/path-table	N/A	9.3 µs	N/A
🆕	matchit benchmarks/path-tree	N/A	7.7 µs	N/A
🆕	matchit benchmarks/regex	N/A	19.4 µs	N/A
🆕	matchit benchmarks/route-recognizer	N/A	38.7 µs	N/A
🆕	matchit benchmarks/routefinder	N/A	48.6 µs	N/A
🆕	matchit benchmarks/wayfind	N/A	9.3 µs	N/A
🆕	matchit benchmarks/xitca-router	N/A	7.6 µs	N/A
👁	matchit benchmarks/actix-router	179.6 µs	N/A	N/A
👁	matchit benchmarks/gonzales	4.7 µs	N/A	N/A
👁	matchit benchmarks/matchit	5.4 µs	N/A	N/A
👁	matchit benchmarks/ntex-router	27.6 µs	N/A	N/A
👁	matchit benchmarks/path-table	9.4 µs	N/A	N/A
👁	matchit benchmarks/path-tree	7.9 µs	N/A	N/A
👁	matchit benchmarks/regex	19.4 µs	N/A	N/A
👁	matchit benchmarks/route-recognizer	38.8 µs	N/A	N/A
👁	matchit benchmarks/routefinder	48.8 µs	N/A	N/A
...	...	...	...	...

:information_source: Only the first 20 benchmarks are displayed. Go to the app to view all benchmarks.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

:white_check_mark: All tests successful. No failed tests found.