feat(otopcua): applier pass to materialise discovered nodes idempotently

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

@@ -303,6 +303,45 @@ public sealed class AddressSpaceApplier
             composition.EquipmentTags.Select(t => t.EquipmentId).Distinct(StringComparer.Ordinal).Count());
     }
 
+    /// <summary>
+    ///     Materialise driver-discovered nodes (FixedTree) under an equipment at runtime. Idempotent:
+    ///     re-applies are cheap (the sink's EnsureFolder/EnsureVariable early-return on existing nodes), so
+    ///     this is safely re-run after every address-space rebuild. Folders are ensured parent-first.
+    ///     Emits a NodeAdded model-change so connected clients can refresh. Discovered nodes are read-only
+    ///     value nodes; array discovered nodes (rare) are forced read-only like the equipment-tag pass.
+    /// </summary>
+    /// <param name="equipmentRootNodeId">The equipment root node the discovered nodes hang under; the
+    /// NodeAdded model-change is announced under this node.</param>
+    /// <param name="folders">The discovered folders to ensure (parent-first by depth).</param>
+    /// <param name="variables">The discovered variables to ensure (read-only value nodes).</param>
+    public void MaterialiseDiscoveredNodes(
+        string equipmentRootNodeId,
+        IReadOnlyList<DiscoveredFolder> folders,
+        IReadOnlyList<DiscoveredVariable> variables)
+    {
+        ArgumentNullException.ThrowIfNull(folders);
+        ArgumentNullException.ThrowIfNull(variables);
+        if (folders.Count == 0 && variables.Count == 0) return;
+
+        // Parent-first: a child folder's parent must exist before it. Ordering by '/' count == depth.
+        foreach (var f in folders.OrderBy(f => f.NodeId.Count(c => c == '/')))
+            SafeEnsureFolder(f.NodeId, f.ParentNodeId, f.DisplayName);
+
+        foreach (var v in variables)
+        {
+            // Mirror MaterialiseEquipmentTags: arrays forced read-only (the driver write path can't handle arrays).
+            var writable = v.Writable && !v.IsArray;
+            SafeEnsureVariable(v.NodeId, v.ParentNodeId, v.DisplayName, v.DataType, writable,
+                historianTagname: null, isArray: v.IsArray, arrayLength: v.ArrayLength);
+        }
+
+        _sink.RaiseNodesAddedModelChange(equipmentRootNodeId);
+
+        _logger.LogInformation(
+            "AddressSpaceApplier: discovered nodes materialised under {Equipment} (folders={Folders}, vars={Vars})",
+            equipmentRootNodeId, folders.Count, variables.Count);
+    }
+
     /// <summary>
     ///     Materialise Equipment-namespace VirtualTags from a composition snapshot — the VirtualTag
     ///     analogue of <see cref="MaterialiseEquipmentTags"/>. For each <see cref="EquipmentVirtualTagPlan"/>,

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

@@ -88,4 +88,8 @@ public sealed class SdkAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgicalAddre
 
     /// <summary>Rebuilds the entire OPC UA address space.</summary>
     public void RebuildAddressSpace() => _nodeManager.RebuildAddressSpace();
+
+    /// <summary>Announces a runtime NodeAdded model-change (discovered-node injection) to subscribed clients.</summary>
+    /// <param name="affectedNodeId">The node under which discovered nodes were added.</param>
+    public void RaiseNodesAddedModelChange(string affectedNodeId) => _nodeManager.RaiseNodesAddedModelChange(affectedNodeId);
 }