Replace the stringly-typed infra-control path with an InfraContainer enum
(Ci/Forge/Gateway/Matrix). The variants are the allowlist: serde rejects any
unknown or unsafe name (hive-c0re has no variant) at the wire boundary, so
hive-priv no longer needs a root-side SIBLING_CONTAINERS.contains() check on
ControlInfraContainer — the type enforces it, and 'the daemon can't stop
itself' is a compile-time guarantee.
- priv_proto: InfraContainer enum; manual Serialize/Deserialize + FromStr +
unit_name() all key off one mapping, so the wire form ('hive-ci', …) is
unchanged and there's no drift. ControlInfraContainer.container: String ->
InfraContainer.
- hive-priv / priv_client / server.rs: thread the enum; scoped_infra returns
Vec<InfraContainer>; the control handler uses unit_name().
- agent_server: the infra_admin restart gate parses the name via FromStr
instead of a slice .contains().
- SIBLING_CONTAINERS stays (validate_container_name/_system_name still use it
for journals / general container validation); a test keeps the enum and the
slice in lockstep.
cd025b3790