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/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/DeferredAddressSpaceSink.cs

@@ -87,4 +87,17 @@ public sealed class DeferredAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgical
     public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
         => _inner is ISurgicalAddressSpaceSink surgical
            && surgical.UpdateTagAttributes(variableNodeId, writable, historianTagname, dataType, isArray, arrayLength);
+
+    /// <summary>Forwards an in-place folder-display-name update (OpcUaServer-001 — UNS Area / Line
+    /// rename) to the inner sink when it supports the surgical capability. Returns false otherwise —
+    /// before the real <c>SdkAddressSpaceSink</c> is swapped in (inner is still the null sink), or any
+    /// inner sink that isn't surgical — so the caller (AddressSpaceApplier) falls back to a full rebuild.
+    /// Without this forward the rename-refresh optimization is inert on every driver-role host, because
+    /// actors inject THIS wrapper, not the inner sink.</summary>
+    /// <param name="folderNodeId">The folder node id whose display name to update in place.</param>
+    /// <param name="displayName">The new display name to apply.</param>
+    /// <returns>True when the inner sink applied the update; false when it lacks the capability or the folder is missing.</returns>
+    public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+        => _inner is ISurgicalAddressSpaceSink surgical
+           && surgical.UpdateFolderDisplayName(folderNodeId, displayName);
 }

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/ISurgicalAddressSpaceSink.cs

@@ -23,4 +23,15 @@ public interface ISurgicalAddressSpaceSink
     /// <param name="arrayLength">The declared length of the 1-D array when <paramref name="isArray"/> is true; ignored for scalars.</param>
     /// <returns>True when the in-place update was applied; false when the node is missing (caller rebuilds).</returns>
     bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength);
+
+    /// <summary>Update an existing folder node's <c>DisplayName</c> IN PLACE, notifying subscribers
+    /// (ClearChangeMasks) without a rebuild — used by AddressSpaceApplier to apply a UNS Area / Line
+    /// rename without tearing down + repopulating the whole address space (which would drop every
+    /// client's MonitoredItems). The folder's NodeId is unchanged (a rename only touches the friendly
+    /// browse/display name, not the logical id). Returns false if the folder does not exist (caller
+    /// should rebuild instead).</summary>
+    /// <param name="folderNodeId">The node id of the folder 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 (caller rebuilds).</returns>
+    bool UpdateFolderDisplayName(string folderNodeId, string displayName);
 }