fix(opcua,drivers): carry driver status sub-codes to clients (#519) + health-write ordering (#517)

#519 — a driver's OPC UA status code now reaches a client with its sub-code intact.
DriverInstanceActor projected the driver's uint onto a 3-state Good/Uncertain/Bad enum
and OtOpcUaNodeManager re-expanded Bad to a bare 0x80000000, so BadNoCommunication,
BadTypeMismatch and BadNotSupported were indistinguishable on the wire and every
driver's status constants (incl. the 16 #497 had just corrected) were diagnostic in
logs only. Resolved by option (b): the raw uint rides AttributeValuePublished ->
AttributeValueUpdate -> IOpcUaAddressSpaceSink.WriteValue, OpcUaQuality is deleted, and
severity classification is a helper (OpcUaStatus.IsGood/IsUncertain/IsBad).

The surface was wider than the issue costed (41 files, not "the sink and 3
implementations"): OpcUaQuality had non-driver producers with no uint to carry.
Each got its natural code — BadInternalError for a failed virtual-tag script,
BadNoCommunication for driver comms loss — and ScriptedAlarmHostActor's pair of
mutually-inverse uint<->enum mappers is deleted, having round-tripped a code the
engine already held. AddressSpaceApplier's removal writes deliberately keep the
generic Bad: not losing a code the driver had is this issue; inventing one for the
deploy path is a separate call.

Behaviour change: WriteAlarmQuality fires its Part 9 event on a status-code change
rather than a severity-bucket change. While the annotation was 3-state those were the
same predicate; now a move between two Bad reasons changes what a subscriber reads.

New SDK-free named constants live on Commons.OpcUa.OpcUaStatus, and
StatusCodeParityTests is widened to cover them — that guard is reflection-driven, so
it can only see a named constant, never an inline literal.

#517 — the symptom is real but the issue named the wrong path and its fix was unsafe.
ShutdownAsync cannot race: DriverInstanceActor calls it from PostStop, after the
mailbox drains. (Core/Hosting/DriverHost, the one class with a concurrent GetHealth,
has no production call site.) InitializeAsync can: it runs on a fire-and-forget
Task.Run, and MTConnectDriver writes Healthy then starts loops that can throw into a
catch which disposes the client before writing Faulted.

Moving the write earlier, as suggested, inverts the terminal state — teardown drains
in-flight loops that write health as they unwind, so a late loop could leave Healthy at
rest with every connection closed. The fix is a bracket (conservative before, terminal
after), applied to MTConnect's init-failure path only; shutdown keeps its single
trailing write, and the rule plus the reachability table are documented on
IDriver.ShutdownAsync.

CalculationDriver.GetHealth returned a hard-coded Healthy that consulted nothing —
Healthy before initialize, after shutdown and after dispose. Now derived from _running.
Its test, named Health_is_always_Connected, asserted the defect and is replaced.

Every new guard was falsified by breaking the production code and watching it go red.
The two sub-code tests each assert two different Bad codes, since a single-code
assertion could pass against a hard-coded constant under the old projection.

Pre-existing failures, verified unchanged on a stashed tree and not chased: 4 in
Driver.AbLegacy.IntegrationTests (slc500/micrologix/plc5 fixtures not up) and 3 in
Host.IntegrationTests.

Closes #517
Closes #519

Claude-Session: https://claude.ai/code/session_015p7wGqy3YpZNCpDzTpGMKo

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/OpcUa/OpcUaPublishActor.cs

@@ -42,10 +42,12 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     /// <summary>A driver/vtag value update for a single materialised Variable node. v3 Batch 4: carries the
     /// node's <see cref="AddressSpaceRealm"/> so the sink resolves the right namespace — the driver fan-out
     /// posts one of these per registered NodeId (the raw node in <see cref="AddressSpaceRealm.Raw"/> and each
-    /// referencing UNS node in <see cref="AddressSpaceRealm.Uns"/>) with identical value/quality/timestamp.
+    /// referencing UNS node in <see cref="AddressSpaceRealm.Uns"/>) with identical value/status/timestamp.
     /// <see cref="Realm"/> defaults to <see cref="AddressSpaceRealm.Uns"/> so pre-v3 callers (VirtualTag
-    /// equipment nodes) keep compiling; the driver fan-out passes it EXPLICITLY per node.</summary>
-    public sealed record AttributeValueUpdate(string NodeId, object? Value, OpcUaQuality Quality, DateTime TimestampUtc, AddressSpaceRealm Realm);
+    /// equipment nodes) keep compiling; the driver fan-out passes it EXPLICITLY per node.
+    /// <para><see cref="StatusCode"/> is the full OPC UA status code, sub-code included (#519); the sink
+    /// hands it to the SDK verbatim.</para></summary>
+    public sealed record AttributeValueUpdate(string NodeId, object? Value, uint StatusCode, DateTime TimestampUtc, AddressSpaceRealm Realm);
 
     /// <summary>Carries the full Part 9 condition state for a scripted alarm to the sink. The
     /// <paramref name="State"/> snapshot is the Commons projection the Runtime host maps from the engine's
@@ -59,14 +61,14 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     /// scripted alarms (default), <see cref="AddressSpaceRealm.Raw"/> for v3 native raw conditions.</param>
     public sealed record AlarmStateUpdate(string AlarmNodeId, AlarmConditionSnapshot State, DateTime TimestampUtc, AddressSpaceRealm Realm);
     /// <summary>#477 — annotate a materialised condition's source-data Quality out of band from any alarm
-    /// transition (the driver-connectivity path: comms lost → <see cref="OpcUaQuality.Bad"/>, restored →
-    /// <see cref="OpcUaQuality.Good"/>). Routed to <see cref="IOpcUaAddressSpaceSink.WriteAlarmQuality"/>,
-    /// which sets ONLY Quality and fires one Part 9 event on a quality-bucket change.</summary>
+    /// transition (the driver-connectivity path: comms lost → <see cref="OpcUaStatus.BadNoCommunication"/>,
+    /// restored → <see cref="OpcUaStatus.Good"/>). Routed to <see cref="IOpcUaAddressSpaceSink.WriteAlarmQuality"/>,
+    /// which sets ONLY Quality and fires one Part 9 event on a status-code change.</summary>
     /// <param name="AlarmNodeId">The condition node id (RawPath for a native alarm).</param>
-    /// <param name="Quality">The source-data quality to annotate.</param>
+    /// <param name="StatusCode">The source-data status code to annotate, sub-code included.</param>
     /// <param name="TimestampUtc">The connectivity transition timestamp in UTC.</param>
     /// <param name="Realm">The namespace realm the condition lives in (<see cref="AddressSpaceRealm.Raw"/> for native).</param>
-    public sealed record AlarmQualityUpdate(string AlarmNodeId, OpcUaQuality Quality, DateTime TimestampUtc, AddressSpaceRealm Realm);
+    public sealed record AlarmQualityUpdate(string AlarmNodeId, uint StatusCode, DateTime TimestampUtc, AddressSpaceRealm Realm);
     /// <summary>
     ///     Triggers an address-space rebuild. <paramref name="DeploymentId"/> is the deployment
     ///     just applied by the host; the rebuild loads THAT artifact so materialisation matches the
@@ -306,7 +308,7 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     {
         try
         {
-            _sink.WriteValue(msg.NodeId, msg.Value, msg.Quality, msg.TimestampUtc, msg.Realm);
+            _sink.WriteValue(msg.NodeId, msg.Value, msg.StatusCode, msg.TimestampUtc, msg.Realm);
             Interlocked.Increment(ref _writes);
             OtOpcUaTelemetry.OpcUaSinkWrite.Add(1, new KeyValuePair<string, object?>("kind", "value"));
         }
@@ -334,7 +336,7 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     {
         try
         {
-            _sink.WriteAlarmQuality(msg.AlarmNodeId, msg.Quality, msg.TimestampUtc, msg.Realm);
+            _sink.WriteAlarmQuality(msg.AlarmNodeId, msg.StatusCode, msg.TimestampUtc, msg.Realm);
             Interlocked.Increment(ref _writes);
             OtOpcUaTelemetry.OpcUaSinkWrite.Add(1, new KeyValuePair<string, object?>("kind", "alarm-quality"));
         }