370a2b7b48
T21: add an AdminUI path for acknowledging/shelving alarms that routes through the admin-pinned AdminOperationsActor cluster singleton, which republishes onto the same 'alarm-commands' DPS topic the OPC UA method path (T18) and the engine subscriber (T19) use. The broadcast + the ScriptedAlarmHostActor ownership filter handle cross-node routing, so the singleton needs no knowledge of which node owns the alarm. - Commons: AcknowledgeAlarmCommand/ShelveAlarmCommand (+ result records) and a shared AlarmCommandsTopic const; ScriptedAlarmHostActor now re-exports that const (mirrors the DriverControlTopic pattern). - AdminOperationsActor: two handlers map the control-plane messages to AlarmCommand (Acknowledge / OneShotShelve / TimedShelve / Unshelve, threading User/Comment/UnshelveAtUtc) and publish via the DPS mediator. - IAdminOperationsClient + AdminOperationsClient: typed Acknowledge/Shelve ask wrappers mirroring StartDeploymentAsync. - Alerts.razor: per-row DriverOperator-gated Ack/Shelve/Unshelve controls; operator name from AuthenticationState. Timed-shelve datetime UI deferred. - 5 TestKit tests (mediator-probe subscribed to alarm-commands) verifying each kind's mapping + reply; 56/56 ControlPlane tests green.