fix(native-alarms): a 4-column CSV import keeps stored MES overrides on the CLI path too (ScadaBridge#104)

The bulk SetInstanceNativeAlarmSourceOverridesCommand handler always wrote the
entry's IsMesReportableOverride, so a CLI import of a legacy 4-column CSV (no
MesReportable column) reset every imported source's MES override to inherit. The
Central UI avoided it only by looking up the stored flag client-side.

NativeAlarmSourceOverrideEntry gains an additive trailing KeepStoredMesReportable
flag: when set, the server leaves an existing row's MES override untouched (a new
row inherits) and ignores IsMesReportableOverride; unset keeps the old meaning
(null = clear to inherit), so older senders are unaffected. The CLI and the Central
UI now build their entries through one rule (ToOverrideEntry on each row type):
no MesReportable column => KeepStoredMesReportable. CLI README and
Component-CentralUI updated.

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

src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs

@@ -1371,7 +1371,9 @@ public class ManagementActor : ReceiveActor
                     ConnectionNameOverride = entry.ConnectionNameOverride,
                     SourceReferenceOverride = entry.SourceReferenceOverride,
                     ConditionFilterOverride = entry.ConditionFilterOverride,
-                    IsMesReportableOverride = entry.IsMesReportableOverride
+                    // ScadaBridge#104: an entry that leaves the MES flag unspecified keeps the
+                    // stored value — for a new row that is "inherit".
+                    IsMesReportableOverride = entry.KeepStoredMesReportable ? null : entry.IsMesReportableOverride
                 };
                 await repo.AddInstanceNativeAlarmSourceOverrideAsync(ovr);
                 results.Add(ovr);
@@ -1381,7 +1383,8 @@ public class ManagementActor : ReceiveActor
                 existing.ConnectionNameOverride = entry.ConnectionNameOverride;
                 existing.SourceReferenceOverride = entry.SourceReferenceOverride;
                 existing.ConditionFilterOverride = entry.ConditionFilterOverride;
-                existing.IsMesReportableOverride = entry.IsMesReportableOverride;
+                if (!entry.KeepStoredMesReportable)
+                    existing.IsMesReportableOverride = entry.IsMesReportableOverride;
                 await repo.UpdateInstanceNativeAlarmSourceOverrideAsync(existing);
                 results.Add(existing);
             }