refactor(transport): single-source template child equality — diff and overwrite-sync can no longer drift

New TemplateChildEquality is the one place "has this template child changed?" is
decided, comparing the COMPLETE writable field set per entity (attributes now incl.
ElementDataType + LockedInDerived; alarms incl. the on-trigger script by name +
LockedInDerived; scripts incl. MinTimeBetweenRuns/ExecutionTimeoutSeconds +
LockedInDerived; native sources per T5). ArtifactDiff.CompareTemplate and all four
BundleImporter.SyncTemplate*Async predicates now route through it — closing the
class of bug where Preview reported Identical for an artifact an Overwrite would
mutate. The attribute sync passes a value-normalised DTO so List-value re-imports
stay idempotent; the alarm on-trigger change now surfaces in both diff and sync.

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

src/ZB.MOM.WW.ScadaBridge.Transport/Import/ArtifactDiff.cs

@@ -64,16 +64,23 @@ public sealed class ArtifactDiff
         AddIfDifferent(changes, "FolderName", FolderNameOf(existing), incoming.FolderName);
         AddIfDifferent(changes, "BaseTemplateName", BaseTemplateNameOf(existing), incoming.BaseTemplateName);
 
+        // Bundles reference the alarm on-trigger script by name; resolve the
+        // persisted FK back to a name over this template's own scripts so the
+        // shared equality can compare it. See TemplateChildEquality.
+        var scriptNameById = TemplateChildEquality.ScriptNameResolver(existing.Scripts);
+
         // Children: compare each child collection by name. We track which names
         // were added, which were removed, and which existed on both sides but
         // diverged in body. We use coarse value equality / line counts for
-        // scripts so the diff JSON stays under a few KB per item.
+        // scripts so the diff JSON stays under a few KB per item. Change
+        // detection is single-sourced through TemplateChildEquality so the diff
+        // can never disagree with what an Overwrite sync writes (#05-T6).
         DiffChildren(
             existing.Attributes,
             incoming.Attributes,
             e => e.Name,
             i => i.Name,
-            AttributesEqual,
+            TemplateChildEquality.AttributesEqual,
             "Attributes",
             changes);
 
@@ -82,7 +89,7 @@ public sealed class ArtifactDiff
             incoming.Alarms,
             e => e.Name,
             i => i.Name,
-            AlarmsEqual,
+            (e, i) => TemplateChildEquality.AlarmsEqual(e, i, scriptNameById),
             "Alarms",
             changes);
 
@@ -106,7 +113,7 @@ public sealed class ArtifactDiff
             incoming.NativeAlarmSources,
             e => e.Name,
             i => i.Name,
-            NativeAlarmSourcesEqual,
+            TemplateChildEquality.NativeAlarmSourcesEqual,
             "NativeAlarmSources",
             changes);
 
@@ -641,7 +648,7 @@ public sealed class ArtifactDiff
         foreach (var (name, ex) in existingByName)
         {
             if (!incomingByName.TryGetValue(name, out var inc)) continue;
-            if (!ScriptsEqual(ex, inc))
+            if (!TemplateChildEquality.ScriptsEqual(ex, inc))
             {
                 // A script row can diverge in Code and/or its trigger/param metadata.
                 // The structured line diff covers the Code body; when only the
@@ -652,37 +659,6 @@ public sealed class ArtifactDiff
         }
     }
 
-    private static bool AttributesEqual(TemplateAttribute e, TemplateAttributeDto i) =>
-        e.Value == i.Value
-        && e.DataType == i.DataType
-        && e.IsLocked == i.IsLocked
-        && e.Description == i.Description
-        && e.DataSourceReference == i.DataSourceReference;
-
-    private static bool AlarmsEqual(TemplateAlarm e, TemplateAlarmDto i) =>
-        e.Description == i.Description
-        && e.PriorityLevel == i.PriorityLevel
-        && e.TriggerType == i.TriggerType
-        && e.TriggerConfiguration == i.TriggerConfiguration
-        && e.IsLocked == i.IsLocked;
-
-    private static bool ScriptsEqual(TemplateScript e, TemplateScriptDto i) =>
-        string.Equals(e.Code, i.Code, StringComparison.Ordinal)
-        && e.TriggerType == i.TriggerType
-        && e.TriggerConfiguration == i.TriggerConfiguration
-        && e.ParameterDefinitions == i.ParameterDefinitions
-        && e.ReturnDefinition == i.ReturnDefinition
-        && e.IsLocked == i.IsLocked;
-
-    private static bool NativeAlarmSourcesEqual(TemplateNativeAlarmSource e, TemplateNativeAlarmSourceDto i) =>
-        e.Description == i.Description
-        && e.ConnectionName == i.ConnectionName
-        && e.SourceReference == i.SourceReference
-        && e.ConditionFilter == i.ConditionFilter
-        && e.IsLocked == i.IsLocked
-        && e.IsInherited == i.IsInherited
-        && e.LockedInDerived == i.LockedInDerived;
-
     private static bool ExternalSystemMethodsEqual(ExternalSystemMethod e, ExternalSystemMethodDto i) =>
         e.HttpMethod == i.HttpMethod
         && e.Path == i.Path