fix(code-review): resolve OpcUaServer-001 — UNS Area/Line rename refreshes folder DisplayName

A rename-only deploy produced an IsEmpty plan that short-circuited before MaterialiseHierarchy,
leaving the OPC UA folder DisplayName stale. AddressSpacePlanner now diffs UnsAreas/UnsLines by
stable id into a RenamedFolders set (counted in IsEmpty); the applier refreshes the folder in
place via a new UpdateFolderDisplayName on ISurgicalAddressSpaceSink (forwarded through
DeferredAddressSpaceSink so it is NOT inert on driver hosts; falls back to rebuild when the sink
is non-surgical). DeploymentArtifact byte-parity untouched (rename rides the existing Name
round-trip). No EF migration, no serialized wire/proto contract change. +13 OpcUaServer tests, Runtime rebuild test.

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

@@ -77,6 +77,15 @@ public sealed class SdkAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgicalAddre
     public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
         => _nodeManager.UpdateTagAttributes(variableNodeId, writable, historianTagname, dataType, isArray, arrayLength);
 
+    /// <summary>OpcUaServer-001: surgically update an existing folder node's display name in place (no
+    /// rebuild) for a UNS Area / Line rename. Returns false when the folder does not exist (caller falls
+    /// back to a full rebuild).</summary>
+    /// <param name="folderNodeId">The folder node identifier whose display name to update in place.</param>
+    /// <param name="displayName">The new display name to apply.</param>
+    /// <returns>True when the in-place update was applied; false when the folder is missing.</returns>
+    public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+        => _nodeManager.UpdateFolderDisplayName(folderNodeId, displayName);
+
     /// <summary>Rebuilds the entire OPC UA address space.</summary>
     public void RebuildAddressSpace() => _nodeManager.RebuildAddressSpace();
 }