fix(adminui): alias update pins invariants + LoadAliasTagAsync + null-driver guard (review)

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Uns/IUnsTreeService.cs

@@ -175,6 +175,12 @@ public interface IUnsTreeService
     /// <returns>The tag's edit projection, or <c>null</c> when missing.</returns>
     Task<TagEditDto?> LoadTagAsync(string tagId, CancellationToken ct = default);
 
+    /// <summary>Load a Galaxy alias tag for editing (FullName parsed from TagConfig). Null if not found.</summary>
+    /// <param name="tagId">The alias tag to load.</param>
+    /// <param name="ct">A token to cancel the load.</param>
+    /// <returns>The alias tag's edit projection, or <c>null</c> when missing.</returns>
+    Task<AliasTagEditDto?> LoadAliasTagAsync(string tagId, CancellationToken ct = default);
+
     /// <summary>
     /// Loads a single equipment-bound virtual tag projected for editing, or <c>null</c> if it no longer
     /// exists. Reads untracked and captures the current concurrency token for last-write-wins saves.