- migration-plan.md: workstation-only migration of nh3-dev's dev env to
the M2 Ultra Mac Pro Rack (on-subnet, sidecars stay on Linux).
- nh3-dev README: drop volva from live sidecars + add retired note.
volva.service/heid.service removed by infra-ops at heid's request
(re-architected daemon->CC-orchestrator; volva.service was crash-looping).
