Hoist control-plane auth provisioning out of the per-backend launchers into
one shared contract, parameterized per trust domain (#476). Every blocking
finding in PR #471 was the same integration-bug class: each launcher
re-derived, by hand, how to generate the signing key, scope it to the
orchestrator, mint the gateway JWT, and keep the host key canonical.
Introduces `trust_domain.py`:
* `TrustDomain` — one credential boundary (host-canonical key file + role
set + env vars). `mint`/`verify` are scoped to the domain's roles, so a
future host-controller domain (#468) uses its own key/verifier/roles
rather than a `host` role on the control plane's frozenset (which the
orchestrator key could then forge).
* `ControlPlaneProvisioning` — the single seam answering the four
invariants: host-canonical key, split key-vs-token credential, CLI token
valid across co-running backends, and fail-closed (no open mode) for any
co-located topology.
* `Topology` — the backend declares what it is; the default is co-located +
fail-closed, so a backend need not redeclare it.
The `Orchestrator` ABC gets `control_plane_key()` (fail-closed) and routes
`mint_gateway_token()` through the contract; docker/macOS/firecracker
orchestrators, the server (verify), and the host CLI client (mint cli) all go
through the domain instead of reading the host key directly. `orchestrator_auth`
gains an optional `roles=` arg (default unchanged) so a domain scopes its own
role set; `paths.host_signing_key(filename)` generalizes host_orchestrator_token.
Adds unit coverage for the domain boundary + provisioning invariants and a PRD
capturing the durable rationale. No change to the auth primitive's HMAC, the
plane split, or the server's documented open-mode fallback.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Closes#476
didericis-claude
45f3cefbc5