feat(streaming): carry IsMesReportable on AlarmStateUpdate (25) and DebugAlarmStateDto (20) (ScadaBridge#60)

Central's Debug View live stream and Alarm Summary cache always saw false
because neither wire message had the field. Additive proto fields, vendored
C# regenerated with docker/regen-proto.sh (sitestream + sitecommand), mapped
both ways in StreamRelayActor/SiteStreamGrpcClient and SiteCommandDtoMapper.
The live stream publishes Alarm Actor events, which never carried the flag,
so InstanceActor.HandleAlarmStateChanged now stamps it before retaining and
publishing. A pre-#60 site sends the proto3 default. No UI badge yet.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

src/ZB.MOM.WW.ScadaBridge.Communication/Grpc/SiteStreamGrpcClient.cs

@@ -605,7 +605,9 @@ public class SiteStreamGrpcClient : IAsyncDisposable, IDisposable
             IsConfiguredPlaceholder = evt.AlarmChanged.IsConfiguredPlaceholder,
             // MES alarm-status API §6.4: ack instant; an absent proto Timestamp (unacked
             // condition, computed alarm, or a pre-AckTime site) stays null.
-            AckTime = evt.AlarmChanged.AckTime?.ToDateTimeOffset()
+            AckTime = evt.AlarmChanged.AckTime?.ToDateTimeOffset(),
+            // Gitea #60: a pre-#60 site leaves the field at its proto3 default (false).
+            IsMesReportable = evt.AlarmChanged.IsMesReportable
         },
         _ => null
     };