The gateway now populates Runtime.dbo.Events.Source_Object from the event
SourceName (gateway C4 fix: HistorianProtoMapper threads SourceName into the
`source_object` event property). So an ad-hoc alarm SendEvent is now source-
filterable on readback, and Alarm_SendEvent_then_ReadEvents asserts the round-
trip instead of skipping with the old "ad-hoc sends land without Source_Object"
reason. Poll window widened to 60s for the live event-view flush latency.
Live-proven at the gateway level (HistorianGateway EventSourceObjectProbeTests,
2026-06-27); this asserts the same round-trip through the OtOpcUa alarm writer +
data source adapters.
Claude-Session: https://claude.ai/code/session_012SDSQ3AcaXqPcBtDESBRii