feat(v3-batch4-wp2): node manager dual-namespace + realm-aware sink surface

Register both v3 namespaces (Raw first, UNS second) on OtOpcUaNodeManager and
thread an AddressSpaceRealm discriminator through every node-naming sink method
so a bare node id is resolved to the correct namespace by realm — never parsed
out of the id string.

- IOpcUaAddressSpaceSink / ISurgicalAddressSpaceSink: every node-naming method
  gains `AddressSpaceRealm realm = AddressSpaceRealm.Uns` (transitional default so
  un-migrated WP3 call sites still compile; WP3/Wave B makes them explicit and
  removes the default). Null + SdkAddressSpaceSink impls updated; DeferredAddress-
  SpaceSink forwards realm through every method (the forwarding trap).
- DeferredSinkForwardingReflectionTests: existing exhaustive-forwarding guard
  auto-covers the new signatures; added an explicit guard that every node-naming
  sink method carries an AddressSpaceRealm parameter (RebuildAddressSpace exempt).
- OtOpcUaNodeManager: register RawNamespaceUri + UnsNamespaceUri; realm->namespace
  index via NamespaceIndexForRealm; all node maps (_variables/_folders/
  _alarmConditions/_nativeAlarmNodeIds/_historizedTagnames/_eventNotifierSources)
  re-keyed by the full ns-qualified NodeId string so Raw and UNS nodes sharing a
  bare id stay distinct; _notifierFolders already NodeId-keyed. A historized UNS
  reference node registers the SAME historian tagname as its backing raw node
  (both NodeIds -> one tagname). Inbound-write hook routes the full ns-qualified
  NodeId to the write gateway (realm-aware) and reverts by bare id + realm.
  HistoryRead seams resolve via NodeId directly. DefaultNamespaceUri kept as a
  transitional alias to UnsNamespaceUri for the SubscriptionSurvivalTests.
- Test doubles across Commons.Tests / OpcUaServer.Tests / Runtime.Tests updated to
  the new interface signatures; SdkAddressSpaceSinkTests asserts the UNS namespace
  index for default-realm nodes.

Build: dotnet build ZB.MOM.WW.OtOpcUa.slnx = 0 errors.
Tests: Commons.Tests 310/310; OpcUaServer.Tests 335 passed / 4 pre-existing skips.

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

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/SdkAddressSpaceSinkTests.cs

@@ -111,11 +111,14 @@ public sealed class SdkAddressSpaceSinkTests : IDisposable
         condition.ShouldNotBeNull();
         // It is a REAL Part 9 alarm condition (subtype mapped from "OffNormalAlarm").
         condition.ShouldBeOfType<OffNormalAlarmState>();
-        condition.NodeId.ShouldBe(new NodeId("alm-1", nm.NamespaceIndex));
+        // v3 dual-namespace: the sink's transitional default realm is UNS, so default-realm nodes live in the
+        // UNS namespace (index 3), not the Raw namespace nm.NamespaceIndex (index 2) reports.
+        var unsNs = nm.NamespaceIndexForRealm(AddressSpaceRealm.Uns);
+        condition.NodeId.ShouldBe(new NodeId("alm-1", unsNs));
 
         // Reachable under the equipment folder: the parent is the eq-1 folder (HasComponent child).
         condition.Parent.ShouldNotBeNull();
-        condition.Parent!.NodeId.ShouldBe(new NodeId("eq-1", nm.NamespaceIndex));
+        condition.Parent!.NodeId.ShouldBe(new NodeId("eq-1", unsNs));
 
         // Initial state set by MaterialiseAlarmCondition: enabled, inactive, acked, retain=false.
         condition.EnabledState.Id.Value.ShouldBeTrue();