feat(alarms): condition Quality tracks source connectivity (#477)

Part 9 ConditionType.Quality was never assigned; default(StatusCode)==Good
so every native + scripted condition reported Good unconditionally — a
comms-lost device still showed a healthy, inactive, Good condition (a
wrong-VALUE bug, distinct from the null-value #473/#475). Clients (and HMIs
bucketing on IsGood) could not tell "genuinely inactive" from "lost contact".

Layer 1 — make Quality a real, plumbed field:
- AlarmConditionSnapshot gains OpcUaQuality Quality (default Good).
- MaterialiseAlarmCondition sets it (native BadWaitingForInitialData, scripted Good).
- WriteAlarmCondition projects snapshot.Quality; the delta-gate gains a Quality
  member so a quality-bucket change fires a Part 9 event.

Layer 2 — drive native quality from driver connectivity (a comms-lost driver
emits no alarm transitions, and an alarm-bearing raw tag has no value variable,
so quality can't come from either existing channel):
- DriverInstanceActor Tells parent ConnectivityChanged on Connected/Reconnecting.
- DriverHostActor fans it to every native condition the driver owns as
  OpcUaPublishActor.AlarmQualityUpdate (Good on connect, Bad on disconnect).
- New dedicated IOpcUaAddressSpaceSink.WriteAlarmQuality sets ONLY Quality and
  fires only on a bucket change — never touches Active/Acked/Retain (an active
  alarm that loses comms stays active). Not a full-snapshot re-projection, so it
  can't clobber severity/message and works for a never-fired condition.
  Forwarded through DeferredAddressSpaceSink (F10b trap; auto-verified by the
  reflection forwarding guard). Ungated by redundancy role; no /alerts row.

Scripted conditions stay Good; worst-of-input quality deferred to #478 (Layer 3).

Tests: node-level (materialise/project/no-clobber/unknown-node no-op),
NativeAlarmProjector, DriverInstanceActor connectivity emission, DriverHostActor
fan-out, OpcUaPublishActor routing, and the wire-level guard
(Condition_event_Quality_tracks_source_connectivity_on_the_wire) — RED-verified
against a simulated pre-fix always-Good server. Existing DriverInstanceActor
parent probes ignore the new ConnectivityChanged.

Docs: docs/AlarmTracking.md §"Condition source-data Quality (#477)";
design doc docs/plans/2026-07-17-alarm-condition-quality-477-design.md.

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverInstanceActorNativeAlarmTests.cs

@@ -30,6 +30,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -77,6 +80,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -110,6 +116,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new SubscribableOnlyStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -170,6 +179,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
         // Long reconnect interval (default 10 s) so the retry doesn't fire during the assertion window.
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver));
 
         // Drive to Connected; confirm the alarm handler is attached.
@@ -217,6 +229,9 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
     {
         var driver = new AlarmSourceStubDriver();
         var parent = CreateTestProbe();
+        // #477: DriverInstanceActor now Tells the parent ConnectivityChanged on each connect/
+        // disconnect; these tests assert on the data/alarm/discovery forwards, so ignore it.
+        parent.IgnoreMessages(m => m is DriverInstanceActor.ConnectivityChanged);
         var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
@@ -245,6 +260,33 @@ public sealed class DriverInstanceActorNativeAlarmTests : RuntimeActorTestBase
         parent.ExpectNoMsg(TimeSpan.FromMilliseconds(300));
     }
 
+    /// <summary>#477 Layer 2 — the actor announces connectivity to its parent (the host): Connected on
+    /// reaching the Connected state, then Connected=false on a <see cref="DriverInstanceActor.DisconnectObserved"/>,
+    /// then Connected=true again on the reconnect. This is the signal the host uses to annotate the driver's
+    /// native alarm conditions' Quality (comms lost → Bad, restored → Good).</summary>
+    [Fact]
+    public void ConnectivityChanged_is_announced_to_parent_on_connect_disconnect_and_reconnect()
+    {
+        var driver = new AlarmSourceStubDriver();
+        var parent = CreateTestProbe(); // deliberately does NOT ignore ConnectivityChanged — it's the subject.
+        var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, reconnectInterval: TimeSpan.FromMilliseconds(50)));
+
+        actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
+
+        // Initial connect → Connected=true.
+        parent.FishForMessage<DriverInstanceActor.ConnectivityChanged>(m => true, TimeSpan.FromSeconds(3))
+            .Connected.ShouldBeTrue();
+
+        // Disconnect → Connected=false (this is what drives the conditions Bad).
+        actor.Tell(new DriverInstanceActor.DisconnectObserved("backend blip"));
+        parent.FishForMessage<DriverInstanceActor.ConnectivityChanged>(m => true, TimeSpan.FromSeconds(3))
+            .Connected.ShouldBeFalse();
+
+        // Reconnect → Connected=true again (drives them back Good).
+        parent.FishForMessage<DriverInstanceActor.ConnectivityChanged>(m => true, TimeSpan.FromSeconds(3))
+            .Connected.ShouldBeTrue();
+    }
+
     // --- stub drivers ----------------------------------------------------------------------------
 
     private class StubDriver : IDriver