fix(galaxy): invalidate writer handle caches on session reconnect

Add IGalaxyDataWriter.InvalidateHandleCaches() and call it in
GalaxyDriver.ReopenAsync after RecreateAsync succeeds. Prior to this
fix, GatewayGalaxyDataWriter's _itemHandles and _supervisedHandles
dictionaries survived across reconnects, causing the next write to
skip AddItem and AdviseSupervisory against already-dead handles.

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

@@ -293,6 +293,9 @@ public sealed class GalaxyDriver
         if (_ownedMxSession is null) return;
         var clientOptions = BuildClientOptions(_options.Gateway);
         await _ownedMxSession.RecreateAsync(clientOptions, cancellationToken).ConfigureAwait(false);
+        // The recreated session invalidates every prior gw item handle; drop the writer's handle/advise
+        // caches so the next write re-AddItems + re-AdviseSupervisory against the fresh session.
+        _dataWriter?.InvalidateHandleCaches();
     }
 
     /// <summary>