Add stricter clippy rules

[MatthewMckee4]

Summary

Enabled almost all clippy rules, and allowed some extra ones.

Also extracted logic from karva/src/lib.rs into dedicated commands folder.

Test Plan

prek run -a

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 1 untouched benchmark

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_{Comparing strict-clippy (8811c98) with main (3ab75ef)}