Extends GET /api/journal/{name} to also accept the four hive infra
container names (hive-ci, hive-forge, hive-gateway, hive-matrix —
hive_priv_sock::InfraContainer is the allowlist), reusing the same
journalctl -M / hive-priv delegation path already used for agent
containers. Infra containers don't run the per-agent hive daemons, so
the unit filter is skipped for them — always the full machine journal.
Frontend: the AGENT tab's agent selector now lists infra containers
in a separate optgroup (sourced from /api/state's existing
infra_containers field), and disables the unit-filter select when one
is chosen.
66c715842f