fix(v3-batch4-wp2): AddReference sink seam for Organizes UNS→Raw (Wave A review M1)

Close the Wave-A M1 gap: the sink surface had no way to wire the mandated
cross-tree Organizes reference from each UNS reference Variable to its backing
Raw node, forcing WP3 to reopen the frozen surface. Add a dedicated
realm-qualified AddReference method instead.

- IOpcUaAddressSpaceSink.AddReference(sourceNodeId, sourceRealm, targetNodeId,
  targetRealm, referenceType="Organizes"): realm-qualified both ends; idempotent;
  a missing endpoint is a logged no-op (never throws) so a mid-rebuild race can't
  fault a deploy. Base-interface capability (no surgical sniff, no transitional
  default — WP3 wires it explicitly per UNS reference variable).
- SdkAddressSpaceSink forwards to the node manager; DeferredAddressSpaceSink
  forwards unconditionally (like EnsureFolder); NullOpcUaAddressSpaceSink no-ops.
- OtOpcUaNodeManager.AddReference: resolve both nodes by full ns-qualified key
  (variable/folder/condition via ResolveNodeState), guard both-exist, then wire
  the edge bidirectionally (forward Organizes on source, inverse on target) with a
  ReferenceExists idempotency guard + ClearChangeMasks on mutated sides. Reference
  type resolved by ResolveReferenceType (Organizes default). Added internal
  GetNodeReferences test/diagnostic accessor.
- Reflection guard: the exhaustive-forwarding test + the realm-discriminator guard
  auto-cover AddReference (it has two AddressSpaceRealm params) — no edit needed.
- New SdkAddressSpaceSinkTests: Organizes UNS→Raw edge created bidirectionally +
  idempotent; missing endpoint is a safe no-op.
- All 15 IOpcUaAddressSpaceSink test doubles gain the AddReference no-op so the
  solution still builds.

Build: dotnet build ZB.MOM.WW.OtOpcUa.slnx = 0 errors.
Tests: Commons.Tests 310/310; OpcUaServer.Tests 337 passed / 4 pre-existing skips.

Claude-Session: https://claude.ai/code/session_01LVneM3eh1UtJxEisFXgmox

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

@@ -48,6 +48,10 @@ public sealed class DeferredAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgical
     /// <inheritdoc />
     public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) => _inner.RaiseNodesAddedModelChange(affectedNodeId, realm);
 
+    /// <inheritdoc />
+    public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes")
+        => _inner.AddReference(sourceNodeId, sourceRealm, targetNodeId, targetRealm, referenceType);
+
     /// <inheritdoc />
     // Forwards to the inner sink when it supports the surgical capability; returns false otherwise —
     // before the real SdkAddressSpaceSink is swapped in (inner is still the null sink), or any inner

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

@@ -111,6 +111,26 @@ public interface IOpcUaAddressSpaceSink
     /// <param name="realm">The namespace realm <paramref name="affectedNodeId"/> lives in.</param>
     // transitional default — B4-WP3/Wave B makes every call site explicit and removes this default.
     void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns);
+
+    /// <summary>
+    ///     Add an OPC UA reference from an already-materialised source node to an already-materialised
+    ///     target node, both realm-qualified. Used by <c>AddressSpaceApplier</c> to link each UNS reference
+    ///     Variable (source, <see cref="AddressSpaceRealm.Uns"/>) to its backing Raw node (target,
+    ///     <see cref="AddressSpaceRealm.Raw"/>) with an <c>Organizes</c> edge, so the UNS variable
+    ///     browse-resolves to its raw source (and the raw node back via the inverse). The edge is wired
+    ///     bidirectionally (forward on the source, inverse on the target) so browse resolves both ways.
+    ///     <b>Idempotent</b> (an existing edge is not duplicated); a <b>missing endpoint is a no-op</b>
+    ///     (logged, never thrown) so a mid-rebuild race can't fault a deploy.
+    /// </summary>
+    /// <param name="sourceNodeId">The source node's <c>s=</c> id (the referencing node — e.g. the UNS variable).</param>
+    /// <param name="sourceRealm">The namespace realm <paramref name="sourceNodeId"/> lives in.</param>
+    /// <param name="targetNodeId">The target node's <c>s=</c> id (the referenced node — e.g. the backing Raw node).</param>
+    /// <param name="targetRealm">The namespace realm <paramref name="targetNodeId"/> lives in.</param>
+    /// <param name="referenceType">The hierarchical reference type name — <c>Organizes</c> (default),
+    /// <c>HasComponent</c>, or <c>HasProperty</c>; unknown names fall back to <c>Organizes</c>.</param>
+    void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm,
+                      string targetNodeId, AddressSpaceRealm targetRealm,
+                      string referenceType = "Organizes");
 }
 
 /// <summary>OPC UA status code projection — Good / Uncertain / Bad. Real SDK has finer-grained
@@ -144,4 +164,7 @@ public sealed class NullOpcUaAddressSpaceSink : IOpcUaAddressSpaceSink
 
     /// <inheritdoc />
     public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+
+    /// <inheritdoc />
+    public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
 }