Additive RequestedBy on Retry/DiscardSiteCallRequest, plumbed from the Central UI.
On an Applied relay, SiteCallAuditActor emits one best-effort CachedResolve central
direct-write row (Submitted/Discarded) with the operator as Actor. Gated on an
injected ICentralAuditWriter (null in existing tests → no mirror read, unchanged);
the site remains the source of truth for the state change.