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.CLI/Commands/InstanceCommands.cs

@@ -721,10 +721,9 @@ public static class InstanceCommands
                 return 1;
             }
 
-            var overrides = parseResult.Rows
-                .Select(r => new NativeAlarmSourceOverrideEntry(
-                    r.SourceName, r.Connection, r.SourceReference, r.Filter, r.MesReportable))
-                .ToList();
+            // A legacy 4-column file leaves the MES flag unspecified, so the server keeps the
+            // stored overrides (ScadaBridge#104) — the same result as the Central UI import.
+            var overrides = parseResult.Rows.Select(r => r.ToOverrideEntry()).ToList();
             return await CommandHelpers.ExecuteCommandAsync(
                 result, urlOption, formatOption, usernameOption, passwordOption,
                 new SetInstanceNativeAlarmSourceOverridesCommand(id, overrides));