Establish policies/service-dom.md as the service-level companion to the repo
DoI and workstream DoD. Its load-bearing Core criterion is a cheap, side-effect
free health endpoint for availability probing — satisfied by the existing
GET /state/health (DB readiness, 200/503). Served automatically at
/policy/service-dom by the existing policy router.
Add a regression test asserting /state/health returns 200 with the expected
shape, since none existed (DoM Standard criterion #4).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>