safeRmHomeTree and isUnderTestHome answered "is this path under process.env.HOME?".
With test/setup.ts skipped (a bare vitest) HOME is the developer's real home, so every
real file passed, which is how the real linked-cases registry was deleted on 2026-10-10.
They now also require HOME to be the throwaway codeman-vitest-* directory setup.ts
creates, and the shared route harness throws when it is not, so every route test refuses
to start against a real ~/.codeman rather than just the one file that checked.
