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

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

@@ -52,7 +52,7 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
 
         nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
         // Prior state = Good 7; the SDK then optimistically applied 42 (the write the device will reject).
-        nm.WriteValue("eq-1/sp", 7, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
+        nm.WriteValue("eq-1/sp", 7, OpcUaStatus.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
         node.Value = 42; // simulate the SDK's optimistic apply of the rejected write
 
@@ -79,7 +79,7 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/sp", 7, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
+        nm.WriteValue("eq-1/sp", 7, OpcUaStatus.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
         node.Value = 42;
 
@@ -102,7 +102,7 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/sp", 7, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
+        nm.WriteValue("eq-1/sp", 7, OpcUaStatus.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
         node.Value = 99; // a fresh poll already republished the confirmed register value (NOT the optimistic 42)
 
@@ -147,8 +147,8 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
         nm.EnsureVariable("A/B/C/D", parentFolderNodeId: null, displayName: "Raw", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Raw);
         nm.EnsureVariable("A/B/C/D", parentFolderNodeId: null, displayName: "Uns", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
         var now = DateTime.UtcNow;
-        nm.WriteValue("A/B/C/D", 10, OpcUaQuality.Good, now, AddressSpaceRealm.Raw); // raw driver value
-        nm.WriteValue("A/B/C/D", 10, OpcUaQuality.Good, now, AddressSpaceRealm.Uns); // fanned UNS value
+        nm.WriteValue("A/B/C/D", 10, OpcUaStatus.Good, now, AddressSpaceRealm.Raw); // raw driver value
+        nm.WriteValue("A/B/C/D", 10, OpcUaStatus.Good, now, AddressSpaceRealm.Uns); // fanned UNS value
         var raw = nm.TryGetVariable("A/B/C/D", AddressSpaceRealm.Raw)!;
         var uns = nm.TryGetVariable("A/B/C/D", AddressSpaceRealm.Uns)!;
 
@@ -178,8 +178,8 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
         nm.EnsureVariable("A/B/C/D", parentFolderNodeId: null, displayName: "Raw", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Raw);
         nm.EnsureVariable("A/B/C/D", parentFolderNodeId: null, displayName: "Uns", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
         var now = DateTime.UtcNow;
-        nm.WriteValue("A/B/C/D", 10, OpcUaQuality.Good, now, AddressSpaceRealm.Raw);
-        nm.WriteValue("A/B/C/D", 10, OpcUaQuality.Good, now, AddressSpaceRealm.Uns);
+        nm.WriteValue("A/B/C/D", 10, OpcUaStatus.Good, now, AddressSpaceRealm.Raw);
+        nm.WriteValue("A/B/C/D", 10, OpcUaStatus.Good, now, AddressSpaceRealm.Uns);
         var raw = nm.TryGetVariable("A/B/C/D", AddressSpaceRealm.Raw)!;
         var uns = nm.TryGetVariable("A/B/C/D", AddressSpaceRealm.Uns)!;
 
@@ -208,7 +208,7 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/sp", 7, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
+        nm.WriteValue("eq-1/sp", 7, OpcUaStatus.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
 
         var audit = nm.BuildWriteFailureAuditEvent(
@@ -239,7 +239,7 @@ public sealed class NodeManagerWriteRevertTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Int32", writable: true, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/sp", 7, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
+        nm.WriteValue("eq-1/sp", 7, OpcUaStatus.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
 
         var audit = nm.BuildWriteFailureAuditEvent(