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.
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