feat(validation): require TagConfig.FullName on Galaxy alias tags; reframe Tag doc

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Entities/Tag.cs

@@ -3,9 +3,11 @@ using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
 namespace ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 
 /// <summary>
-///     One canonical tag (signal) in a cluster's generation. Per decision #110:
-///     <see cref="EquipmentId"/> is REQUIRED when the driver is in an Equipment-kind namespace
-///     and NULL when in SystemPlatform-kind namespace (Galaxy hierarchy preserved).
+///     One canonical tag (signal) in a cluster's generation. <see cref="EquipmentId"/> set ⟺ the
+///     tag participates in the Equipment tree, regardless of the driver's namespace kind. A
+///     <c>GalaxyMxGateway</c>-bound equipment tag is an <em>alias</em> — a Galaxy attribute surfaced
+///     under a UNS name, with its Galaxy reference carried in <c>TagConfig.FullName</c>.
+///     <see cref="EquipmentId"/> is NULL for SystemPlatform mirror tags (FolderPath-scoped).
 /// </summary>
 public sealed class Tag
 {
@@ -30,8 +32,8 @@ public sealed class Tag
     public string? DeviceId { get; set; }
 
     /// <summary>
-    ///     Required when driver is in Equipment-kind namespace; NULL when in SystemPlatform-kind.
-    ///     Cross-table invariant enforced by sp_ValidateDraft (decision #110).
+    ///     Set when the tag belongs to an Equipment (driver tag OR Galaxy alias); NULL for
+    ///     SystemPlatform mirror tags.
     /// </summary>
     public string? EquipmentId { get; set; }
 

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Validation/DraftValidator.cs

@@ -33,10 +33,43 @@ public static class DraftValidator
         ValidateEquipmentIdDerivation(draft, errors);
         ValidateDriverNamespaceCompatibility(draft, errors);
         ValidateNoEquipmentSignalNameCollision(draft, errors);
+        ValidateAliasTagFullName(draft, errors);
 
         return errors;
     }
 
+    private static void ValidateAliasTagFullName(DraftSnapshot draft, List<ValidationError> errors)
+    {
+        var typeByDriver = draft.DriverInstances
+            .ToDictionary(d => d.DriverInstanceId, d => d.DriverType, StringComparer.Ordinal);
+        foreach (var t in draft.Tags)
+        {
+            if (t.EquipmentId is null) continue;
+            if (!typeByDriver.TryGetValue(t.DriverInstanceId, out var dtype) || dtype != "GalaxyMxGateway")
+                continue;
+            if (string.IsNullOrWhiteSpace(ExtractTagConfigFullName(t.TagConfig)))
+                errors.Add(new("AliasTagMissingReference",
+                    $"Alias tag '{t.TagId}' on equipment '{t.EquipmentId}' is missing a Galaxy reference (TagConfig.FullName)",
+                    t.TagId));
+        }
+    }
+
+    // Minimal reader for the top-level "FullName" string in a tag's schemaless TagConfig JSON
+    // (mirrors Phase7Composer.ExtractTagFullName — a small local copy, consistent with this codebase
+    // where the composer keeps its own).
+    private static string? ExtractTagConfigFullName(string? tagConfig)
+    {
+        if (string.IsNullOrWhiteSpace(tagConfig)) return null;
+        try
+        {
+            using var doc = System.Text.Json.JsonDocument.Parse(tagConfig);
+            return doc.RootElement.ValueKind == System.Text.Json.JsonValueKind.Object
+                && doc.RootElement.TryGetProperty("FullName", out var fn)
+                && fn.ValueKind == System.Text.Json.JsonValueKind.String ? fn.GetString() : null;
+        }
+        catch (System.Text.Json.JsonException) { return null; }
+    }
+
     private static void ValidateNoEquipmentSignalNameCollision(DraftSnapshot draft, List<ValidationError> errors)
     {
         // Materialiser NodeId key: "{EquipmentId}[/{FolderPath}]/{Name}". Tag (EquipmentId != null) and