New POST /api/infra-container/{name}/{action} dashboard route (start/
stop/restart on hive-ci/hive-forge/hive-gateway/hive-matrix), reusing
the existing priv_client::control_infra_container helper the
infra_admin agent path already uses, plus an audit_log entry per
attempt. Adds infra_containers to the /api/state StateSnapshot (name +
live running status via systemctl is-active). New 1NFR4 sub-tab on the
C0R3 dashboard page: one row per infra container with a running/
stopped badge and start/stop/restart buttons, polled every 5s while
the sub-tab is open.