feat(runtime): WithOtOpcUaRuntimeActors extension for driver-role node startup (F19)

Mirrors WithOtOpcUaControlPlaneSingletons for the driver role. Spawns
DriverHostActor + DbHealthProbeActor on the host's ActorSystem and
registers both under marker keys. Host's Program.cs now calls it when
the node carries the driver role, so driver-only and admin+driver
deployments both auto-bootstrap the per-node actors.

Integration test covers the registration round-trip via Microsoft.Extensions.Hosting
+ Akka.Hosting AddAkka.

src/Server/ZB.MOM.WW.OtOpcUa.Host/Program.cs

@@ -8,6 +8,7 @@ using ZB.MOM.WW.OtOpcUa.Configuration;
 using ZB.MOM.WW.OtOpcUa.ControlPlane;
 using ZB.MOM.WW.OtOpcUa.Host;
 using ZB.MOM.WW.OtOpcUa.Host.Health;
+using ZB.MOM.WW.OtOpcUa.Runtime;
 using ZB.MOM.WW.OtOpcUa.Security;
 using ZB.MOM.WW.OtOpcUa.Security.Endpoints;
 
@@ -43,10 +44,8 @@ builder.Services.AddAkka("otopcua", (ab, _) =>
 {
     if (hasAdmin)
         ab.WithOtOpcUaControlPlaneSingletons();
-    // Driver-role startup (DriverHostActor spawn + child probes) is wired in F19 once a
-    // RuntimeStartup contract is added — the actor itself exists (Phase 6), the registration
-    // extension does not yet. Without it, driver-role nodes still join the cluster and serve
-    // health/redundancy traffic but won't auto-spawn DriverHostActor.
+    if (hasDriver)
+        ab.WithOtOpcUaRuntimeActors();
 });
 
 if (hasAdmin)