fix(opcuaclient): upstream session loss goes Bad and recovers (#670)

A bad keep-alive now degrades health (LastSuccessfulRead preserved) and,
once per outage, publishes BadNoCommunication (value retained) for every
subscribed ref plus a quality-only annotation on subscribed alarm
conditions. Good keep-alives and data/event notifications advance
LastSuccessfulRead, so an idle-but-alive subscription never looks dead
to the #527 watchdog. A keep-alive that recovers on the same session
re-reads the Bad refs and republishes them Good; a session that does not
come back is recovered by the watchdog's ShutdownAsync + InitializeAsync
+ re-subscribe.

Deletes the SessionReconnectHandler wiring (it retried forever in SDK
1.5.378, cloned subscriptions the driver never re-tracked and kept health
Healthy), OnReconnectComplete, TryRearmReconnect and the reconnect_*
counters (new keepalive_recovered). Teardown of a lost session skips
wire deletes and bounds CloseSession. SDK warnings reach the driver log.
Wire test reworked: restart => Bad, then watchdog-style reinit => Good.

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests/OpcUaClientReconnectTests.cs

@@ -4,9 +4,10 @@ using Xunit;
 namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests;
 
 /// <summary>
-///     Scaffold tests for <see cref="SessionReconnectHandler"/> wiring. Wire-level
-///     disconnect-reconnect-resume coverage against a live upstream server lands with the
-///     in-process fixture — too much machinery for a unit-test-only lane.
+///     Scaffold tests for the reconnect options. Since Gitea #670 the driver has no in-driver reconnect
+///     handler (session loss is reported and the host's comms-loss watchdog re-initialises the driver);
+///     <c>ReconnectPeriod</c> is retained for config compatibility only. Outage behaviour is covered by
+///     <see cref="OpcUaClientSessionLossTests"/> and, over the wire, <c>OpcUaClientDriverReconnectWireTests</c>.
 /// </summary>
 [Trait("Category", "Unit")]
 public sealed class OpcUaClientReconnectTests
@@ -26,13 +27,10 @@ public sealed class OpcUaClientReconnectTests
         opts.ReconnectPeriod.ShouldBe(TimeSpan.FromMilliseconds(500));
     }
 
-    /// <summary>Verifies that the driver starts with no reconnect handler active before initialization.</summary>
+    /// <summary>Verifies that the driver starts in the Unknown state before initialization.</summary>
     [Fact]
-    public void Driver_starts_with_no_reconnect_handler_active_pre_init()
+    public void Driver_starts_unknown_pre_init()
     {
-        // The reconnect handler is lazy — spun up only when a bad keep-alive fires. Pre-init
-        // there's no session to reconnect, so the field must be null (indirectly verified by
-        // the lifecycle-shape test suite catching any accidental construction).
         using var drv = new OpcUaClientDriver(new OpcUaClientDriverOptions(), "opcua-reconnect");
         drv.GetHealth().State.ShouldBe(Core.Abstractions.DriverState.Unknown);
     }