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.Runtime.Tests/Drivers/CalculationDependencyFlowTests.cs

@@ -63,7 +63,7 @@ public sealed class CalculationDependencyFlowTests : RuntimeActorTestBase
         driver.OnDataChange += (_, e) =>
         {
             published.Enqueue(e);
-            var quality = e.Snapshot.StatusCode == 0u ? OpcUaQuality.Good : OpcUaQuality.Bad;
+            var quality = e.Snapshot.StatusCode == 0u ? OpcUaStatus.Good : OpcUaStatus.Bad;
             mux.Tell(new DriverInstanceActor.AttributeValuePublished(
                 "calc-drv", e.FullReference, e.Snapshot.Value, quality, Ts));
         };
@@ -76,7 +76,7 @@ public sealed class CalculationDependencyFlowTests : RuntimeActorTestBase
         AwaitAssert(() =>
         {
             mux.Tell(new DriverInstanceActor.AttributeValuePublished(
-                "src-drv", "src/a", 21.0, OpcUaQuality.Good, Ts));
+                "src-drv", "src/a", 21.0, OpcUaStatus.Good, Ts));
 
             // Leg 1 — dep flow: src/a=21 → A computes 42 and publishes on calc/engine/out.
             published.ShouldContain(e => e.FullReference == "calc/engine/out" && Equals(e.Snapshot.Value, 42.0));
@@ -117,7 +117,7 @@ public sealed class CalculationDependencyFlowTests : RuntimeActorTestBase
         driver.OnDataChange += (_, e) =>
         {
             published.Enqueue(e);
-            var quality = e.Snapshot.StatusCode == 0u ? OpcUaQuality.Good : OpcUaQuality.Bad;
+            var quality = e.Snapshot.StatusCode == 0u ? OpcUaStatus.Good : OpcUaStatus.Bad;
             mux.Tell(new DriverInstanceActor.AttributeValuePublished("calc-drv", e.FullReference, e.Snapshot.Value, quality, Ts));
         };
         var adapter = Sys.ActorOf(DependencyConsumerMuxAdapter.Props(driver, mux), "dep-adapter2");
@@ -125,7 +125,7 @@ public sealed class CalculationDependencyFlowTests : RuntimeActorTestBase
         // Leg 1 — before redeploy: src/a=2 → keep=20, remove=7.
         AwaitAssert(() =>
         {
-            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/a", 2.0, OpcUaQuality.Good, Ts));
+            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/a", 2.0, OpcUaStatus.Good, Ts));
             published.ShouldContain(e => e.FullReference == "calc/keep" && Equals(e.Snapshot.Value, 20.0));
             published.ShouldContain(e => e.FullReference == "calc/remove" && Equals(e.Snapshot.Value, 7.0));
         }, TimeSpan.FromSeconds(5), TimeSpan.FromMilliseconds(100));
@@ -149,8 +149,8 @@ public sealed class CalculationDependencyFlowTests : RuntimeActorTestBase
         // new result; the REMOVED tag never publishes a value derived from the post-redeploy input.
         AwaitAssert(() =>
         {
-            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/b", 50.0, OpcUaQuality.Good, Ts));
-            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/a", 3.0, OpcUaQuality.Good, Ts));
+            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/b", 50.0, OpcUaStatus.Good, Ts));
+            mux.Tell(new DriverInstanceActor.AttributeValuePublished("src-drv", "src/a", 3.0, OpcUaStatus.Good, Ts));
 
             // (a) new dep B flows through the RE-REGISTERED interest → new tag computes: 50 + 100 = 150.
             published.ShouldContain(e => e.FullReference == "calc/add" && Equals(e.Snapshot.Value, 150.0));