fix(ab-transport): trim-only CIP path canonicalisation, observe abandoned shared opens, no Forward Open after dispose during connect

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport/Cip/CipConnection.cs

@@ -123,7 +123,14 @@ public sealed class CipConnection : ICipChannel, IAsyncDisposable
             }
             pending = _pendingOpen;
         }
-        if (started is not null) _ = RunOpenAsync(started);
+        if (started is not null)
+        {
+            // Every waiter may have abandoned the open (its own token); observe a failure so it never
+            // surfaces as UnobservedTaskException.
+            _ = started.Task.ContinueWith(static t => _ = t.Exception, CancellationToken.None,
+                TaskContinuationOptions.OnlyOnFaulted | TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Default);
+            _ = RunOpenAsync(started);
+        }
         return pending.WaitAsync(ct);
     }
 
@@ -170,6 +177,12 @@ public sealed class CipConnection : ICipChannel, IAsyncDisposable
     {
         ThrowIfDisposed();   // disposal may have begun while this attempt waited out the throttle
         var client = await EncapsulationClient.ConnectAsync(_key.Host, _key.Port, _o.Timeout, ct).ConfigureAwait(false);
+        if (Volatile.Read(ref _disposed) != 0)
+        {
+            // Disposal began during the TCP connect / RegisterSession: never put a Forward Open on the wire.
+            await client.DisposeAsync().ConfigureAwait(false);
+            throw new AbTransportException(AbStatus.Abort, "Connection disposed.");
+        }
         if (_o.Routing != CipRouting.Connected) return new Open(client, null, 0, UnconnectedMessageLimit);
         try
         {