LedgerCommand
A system command of the ledger: an operator's action on subscription's entry of the parked aggregate id of tenantId, of the aggregate type aggregate of context. Its fields are plain values, so any operations tool, not only Wow's own, writes its JSON: {"subscription": ..., "context": ..., "aggregate": ..., "tenantId": ..., "id": ...}. A caller sends it as the system command its name says (Ledger.COMMANDS), which a service's call permits must list explicitly (wow.ledger.*).