The forge and matrix are swarm services; per mara's ruling on #5475
(shape a) a hive no longer starts, stops or restarts them.
- hive-priv-sock: InfraContainer keeps only Gateway; InfraTarget goes,
service_unit maps the gateway to nginx.service directly. A
ControlInfraContainer naming Forge/Matrix fails to decode.
- hive-host-sock: LifecycleScope drops forge/matrix and refuses unknown
fields, so an older hivectl's --forge is an error rather than an
all-false scope meaning everything.
- hive-c0re: scoped_infra selects only the gateway.
- hivectl: --forge/--matrix removed from stop/start/restart.
- docs: services.md says how the forge and matrix are managed;
security.md, coordinator.md and hivectl-cli.md follow.
- hive-host-sock, hivectl/power.rs: Stop and RestartScoped doc comments name the gateway (host nginx.service), not infra containers.
