test(opcua): cover missing-script fallback; rename composer local for clarity

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/Phase7Composer.cs

@@ -190,7 +190,7 @@ public static class Phase7Composer
         IReadOnlyList<Script>? scripts = null)
     {
         var vtags = virtualTags ?? Array.Empty<VirtualTag>();
-        var scripts2 = scripts ?? Array.Empty<Script>();
+        var resolvedScripts = scripts ?? Array.Empty<Script>();
         var areas = unsAreas
             .OrderBy(a => a.UnsAreaId, StringComparer.Ordinal)
             .Select(a => new UnsAreaProjection(a.UnsAreaId, a.Name))
@@ -267,7 +267,7 @@ public static class Phase7Composer
         // Equipment VirtualTags = each VirtualTag joined to its Script (by ScriptId) for the
         // expression source. DependencyRefs = the distinct ctx.GetTag("…") literals the
         // VirtualTagActor subscribes to. VirtualTag has no FolderPath today → "".
-        var scriptsById = scripts2.ToDictionary(s => s.ScriptId, StringComparer.Ordinal);
+        var scriptsById = resolvedScripts.ToDictionary(s => s.ScriptId, StringComparer.Ordinal);
         var equipmentVirtualTags = vtags
             .OrderBy(v => v.EquipmentId, StringComparer.Ordinal)
             .ThenBy(v => v.Name, StringComparer.Ordinal)