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/Runtime/TracedGalaxyDataWriter.cs

@@ -10,6 +10,10 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
 /// </summary>
 internal sealed class TracedGalaxyDataWriter(IGalaxyDataWriter inner, string clientName) : IGalaxyDataWriter
 {
+    /// <inheritdoc />
+    /// <remarks>No span — this is a local cache-clear operation, not a gateway round-trip.</remarks>
+    public void InvalidateHandleCaches() => inner.InvalidateHandleCaches();
+
     /// <summary>Writes data to Galaxy while recording telemetry span.</summary>
     /// <param name="writes">The list of write requests to process.</param>
     /// <param name="securityResolver">Function to resolve security classification for tag references.</param>