f5479f3ca3
Add a nullable string? OwnerKeyId property to GatewaySession that captures the API key identifier (KeyId) of the authenticated caller that opened the session. Wire it through ISessionManager.OpenSessionAsync → SessionManager → GatewaySession constructor. The gRPC service passes identityAccessor .Current?.KeyId; internal callers (GatewayAlarmMonitor, DashboardLiveDataService) pass null. Covers the positive and null cases with two new TDD-first tests.