PR #356 stopped the remote-hosts.json fixture write from clobbering prod.
Two holes in the same file remain:
1. The quick-start afterEach still ran rmSync(CASES_DIR, recursive).
CASES_DIR is join(homedir(), 'codeman-cases'), and on Linux builds
where os.homedir() reads /etc/passwd instead of $HOME it resolves to
the PROD case tree - so a full-suite run deleted the real
~/codeman-cases. Add a shared safeRmHomeTree() containment gate that
only deletes a path under the redirected test HOME.
2. setup.ts teardown did rmSync(process.env.CODEMAN_DATA_DIR ?? '') AFTER
restoring the env - if a pre-existing prod CODEMAN_DATA_DIR was set,
that deleted prod. Capture the throwaway dir in a const and clean that.
A broader test-isolation sweep (10 files: cli-skill-target, edge-cases,
integration-flows, operation-lightspeed, ralph-integration,
case-clone-routes, voice-routes, session-cleanup, sse-events,
sse-subscription-filter) also applies the same containment gates to every
per-case delete. It is intentionally NOT included here to keep this PR
skinny; it is identified and available on request.