fix(virtualtags): a disabled VirtualTag keeps its node and reads BadOutOfService (lmxopcua#787, owner decision)

Revises 963b0d66, which dropped a disabled VirtualTag from the runtime plan so a
bound client got BadNodeIdUnknown. Now the plan carries Enabled (part of value
equality): AddressSpaceComposer.Compose and DeploymentArtifact.BuildEquipmentVirtualTagPlans
keep the row with Enabled=false (byte-parity), the applier materialises the node as
normal, and VirtualTagHostActor spawns no VirtualTagActor for it but publishes
BadOutOfService (new OpcUaStatus constant) with a null value stamped at deploy, on
every apply. Enabled flips are node-irrelevant to the change classifier; enabled->disabled
stops the child, disabled->enabled resumes evaluation. Validator exemption and name
uniqueness unchanged. Scripted alarms keep their not-materialised convention.
Tests updated; new wire test DisabledVirtualTagWireTests. docs/VirtualTags.md updated.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs

@@ -1405,9 +1405,10 @@ internal sealed class ParsedDeploymentArtifact : IDisposable
             if (string.IsNullOrWhiteSpace(virtualTagId) || string.IsNullOrWhiteSpace(equipmentId)
                 || string.IsNullOrWhiteSpace(name)) continue;
 
-            // Enabled (lmxopcua#787): a disabled VirtualTag is not deployed or evaluated — byte-parity with
-            // AddressSpaceComposer.Compose's `.Where(v => v.Enabled)`. Absent/non-bool => the entity default (true).
-            if (el.TryGetProperty("Enabled", out var enEl) && enEl.ValueKind == JsonValueKind.False) continue;
+            // Enabled (lmxopcua#787): a disabled VirtualTag keeps its plan (node materialised, never evaluated,
+            // BadOutOfService) — byte-parity with AddressSpaceComposer.Compose's `Enabled: v.Enabled`.
+            // Absent/non-bool => the entity default (true).
+            var enabled = !(el.TryGetProperty("Enabled", out var enEl) && enEl.ValueKind == JsonValueKind.False);
 
             var source = scriptId is not null && scriptSourceById.TryGetValue(scriptId, out var src)
                 ? src : string.Empty;
@@ -1442,7 +1443,8 @@ internal sealed class ParsedDeploymentArtifact : IDisposable
                 DependencyRefs: EquipmentScriptPaths.ExtractDependencyRefs(expanded),
                 Historize: historize,
                 ChangeTriggered: changeTriggered,
-                TimerIntervalMs: timerMs));
+                TimerIntervalMs: timerMs,
+                Enabled: enabled));
         }
 
         result.Sort((a, b) =>