fix(driver-galaxy): wire event-stream faults to the reconnect supervisor (Driver.Galaxy-001)

The ReconnectSupervisor was constructed but its trigger
ReportTransportFailure was never called. When the gateway StreamEvents
stream faulted, EventPump just logged and exited — the supervisor was
never notified, so a transient gateway drop permanently stopped
data-change notifications while GetHealth() still reported Healthy.

EventPump gains an optional onStreamFault callback invoked from its
stream-fault catch block (not on clean shutdown). GalaxyDriver wires it
to ReconnectSupervisor.ReportTransportFailure so a transport drop drives
reopen → replay.

This is the minimal fix for -001; the pump-restart-on-reopen gap remains
tracked as Driver.Galaxy-008. Regression tests cover the callback being
invoked on fault, the end-to-end supervisor reopen/replay, and that a
clean shutdown does not fire it. Driver.Galaxy suite: 206/206 pass.

Resolves code-review finding Driver.Galaxy-001 (Critical).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs

@@ -732,13 +732,43 @@ public sealed class GalaxyDriver
             _eventPump = new EventPump(
                 _subscriber!, _subscriptions, _logger,
                 channelCapacity: _options.MxAccess.EventPumpChannelCapacity,
-                clientName: _options.MxAccess.ClientName);
+                clientName: _options.MxAccess.ClientName,
+                onStreamFault: OnEventPumpStreamFault);
             _eventPump.OnDataChange += OnPumpDataChange;
             _eventPump.Start();
             return _eventPump;
         }
     }
 
+    /// <summary>
+    ///     Stream-fault callback for the <see cref="EventPump"/>. The gw StreamEvents
+    ///     stream faulted (transient gateway drop, network blip, gw restart). Forward
+    ///     the cause to the <see cref="ReconnectSupervisor"/> so it drives reopen →
+    ///     replay; without this hand-off a transient transport drop permanently kills
+    ///     the event stream and <c>GetHealth()</c> keeps reporting Healthy.
+    /// </summary>
+    private void OnEventPumpStreamFault(Exception cause)
+    {
+        var supervisor = _supervisor;
+        if (supervisor is null)
+        {
+            // No production runtime (skeleton / injected-seam path) — nothing to drive.
+            _logger.LogWarning(cause,
+                "GalaxyDriver {InstanceId} event stream faulted but no reconnect supervisor is wired.",
+                _driverInstanceId);
+            return;
+        }
+
+        try
+        {
+            supervisor.ReportTransportFailure(cause);
+        }
+        catch (ObjectDisposedException)
+        {
+            // Driver is being disposed — the stream fault is just shutdown noise.
+        }
+    }
+
     // ===== IAlarmSource =====
 
     /// <summary>