feat(runtime): HistorianAdapter + PeerOpcUaProbe + DbHealthProbe actors (engine wiring tracked as F11/F12)

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Health/HealthProbeActorTests.cs

@@ -0,0 +1,50 @@
+using Akka.Actor;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+using ZB.MOM.WW.OtOpcUa.Runtime.Health;
+using ZB.MOM.WW.OtOpcUa.Runtime.Historian;
+using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Health;
+
+public sealed class HealthProbeActorTests : RuntimeActorTestBase
+{
+    [Fact]
+    public async Task DbHealthProbeActor_returns_reachable_against_in_memory_db()
+    {
+        var db = NewInMemoryDbFactory();
+        var actor = Sys.ActorOf(DbHealthProbeActor.Props(db));
+
+        var status = await actor.Ask<DbHealthProbeActor.DbHealthStatus>(
+            DbHealthProbeActor.GetStatus.Instance, TimeSpan.FromSeconds(3));
+
+        status.Reachable.ShouldBeTrue();
+        status.LastError.ShouldBeNull();
+    }
+
+    [Fact]
+    public void PeerOpcUaProbeActor_publishes_probe_result_at_each_tick()
+    {
+        var received = new System.Collections.Generic.List<object>();
+        var actor = Sys.ActorOf(PeerOpcUaProbeActor.Props(
+            NodeId.Parse("peer-1"),
+            interval: TimeSpan.FromMilliseconds(50),
+            broadcast: msg => received.Add(msg)));
+
+        AwaitCondition(() => received.Count >= 2, TimeSpan.FromSeconds(2));
+        received.OfType<PeerOpcUaProbeActor.OpcUaProbeResult>().ShouldNotBeEmpty();
+    }
+
+    [Fact]
+    public void HistorianAdapterActor_buffers_rows()
+    {
+        var actor = Sys.ActorOf(HistorianAdapterActor.Props());
+        for (var i = 0; i < 5; i++)
+            actor.Tell(new HistorianAdapterActor.HistoryRow("driver-a", $"tag-{i}", i, DateTime.UtcNow));
+
+        ExpectNoMsg(TimeSpan.FromMilliseconds(100));
+        // No direct readback of the count from a sealed actor — assert by Ask of a self-probe later
+        // when the engine wiring lands (F11). For now this asserts the actor accepts the contract.
+    }
+}