fix(transport): transport template NativeAlarmSources — imports no longer amputate native alarm mirrors nor dangle instance overrides

New TemplateNativeAlarmSourceDto + init-only TemplateDto.NativeAlarmSources (empty
default, additive — IsInherited placeholders carried for the collision detector).
Exported in ToBundleContent, consumed in FromBundleContent + BuildTemplate, and a
new SyncTemplateNativeAlarmSourcesAsync runs the Overwrite add/update/delete child
sync with per-change audit rows. ArtifactDiff.CompareTemplate now DiffChildren over
native sources so Preview reports a NativeAlarmSources field change. Proven by an
end-to-end flatten test: an instance native-alarm-source override that dangled
pre-fix now resolves against the re-imported template source.

Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj

src/ZB.MOM.WW.ScadaBridge.Transport/Serialization/EntitySerializer.cs

@@ -91,7 +91,20 @@ public sealed class EntitySerializer
                         LockedInDerived: s.LockedInDerived)).ToList(),
                     Compositions: t.Compositions.Select(c => new TemplateCompositionDto(
                         InstanceName: c.InstanceName,
-                        ComposedTemplateName: templateNameById.TryGetValue(c.ComposedTemplateId, out var cn) ? cn : string.Empty)).ToList());
+                        ComposedTemplateName: templateNameById.TryGetValue(c.ComposedTemplateId, out var cn) ? cn : string.Empty)).ToList())
+                {
+                    // Native alarm sources carry ALL rows including IsInherited
+                    // placeholders — the collision detector depends on them.
+                    NativeAlarmSources = t.NativeAlarmSources.Select(n => new TemplateNativeAlarmSourceDto(
+                        Name: n.Name,
+                        Description: n.Description,
+                        ConnectionName: n.ConnectionName,
+                        SourceReference: n.SourceReference,
+                        ConditionFilter: n.ConditionFilter,
+                        IsLocked: n.IsLocked,
+                        IsInherited: n.IsInherited,
+                        LockedInDerived: n.LockedInDerived)).ToList(),
+                };
             }).ToList(),
             SharedScripts: aggregate.SharedScripts.Select(s => new SharedScriptDto(
                 Name: s.Name,
@@ -352,6 +365,20 @@ public sealed class EntitySerializer
                         LockedInDerived = s.LockedInDerived,
                     });
                 }
+                foreach (var n in dto.NativeAlarmSources)
+                {
+                    t.NativeAlarmSources.Add(new TemplateNativeAlarmSource(n.Name)
+                    {
+                        TemplateId = t.Id,
+                        Description = n.Description,
+                        ConnectionName = n.ConnectionName,
+                        SourceReference = n.SourceReference,
+                        ConditionFilter = n.ConditionFilter,
+                        IsLocked = n.IsLocked,
+                        IsInherited = n.IsInherited,
+                        LockedInDerived = n.LockedInDerived,
+                    });
+                }
                 return t;
             })
             .ToList();