Driver.Historian.Gateway-001 (High): AlarmEventMapper wrote the alarm's
Severity wire property as the .NET enum name (e.g. "High"), but
EventMapper's read side int.TryParse()s that same property and silently
falls back to the minimum severity on any unparseable value - so every
alarm event's severity round-tripped through this module's own mappers
collapsed to 1 (Low), contradicting AlarmHistorianEvent.Severity's own
documented contract ("mapped to Historian's numeric priority"). Now
mapped through a numeric priority mirroring the existing
NativeAlarmProjector.MapSeverity convention (200/500/700/900).
Driver.Historian.Gateway-002 (Low): GatewayTagProvisioner never disposed
its IHistorianGatewayClient, unlike its GatewayHistorianDataSource /
GatewayAlarmHistorianWriter siblings. Now implements IAsyncDisposable so
the DI-owned singleton's gRPC channel closes gracefully at shutdown.
Both TDD: new/corrected tests confirmed RED against the pre-fix code.
Joseph Doherty
55b12dc217