Thermonuclear review, Kev edition

A review for implementation quality, not correctness: abstraction quality, maintainability, codebase health. Behaviour is assumed to be checked elsewhere (kev-verify). Be ambitious: do not stop at local cleanups. Look for the "code judo" move, a restructuring that keeps behaviour and makes the change dramatically smaller, more direct and more obvious, so that whole branches, helpers, modes or layers disappear. Prefer the version that feels inevitable in hindsight. Measure twice, cut once.

The standards below are adapted from cursor-team-kit's thermo-nuclear-code-quality-review (once vendored next to this file); the second half is what a reviewer needs to apply them to this repository.

Standards