fix: volatile channel fields, disposal race, and ParseHostEndpoint fallback

- Add volatile to _publisherChannel/_subscriberChannel for safe
  double-checked locking on ARM64 (outer null check needs memory barrier)
- Move _publisherReady.Set() after connection close in CleanupAsync to
  prevent unblocked publishers from racing into a disposing channel
- Fix ParseHostEndpoint: invalid port fallback now uses parsed hostname
  instead of the full trimmed string (e.g. "host:abc" -> "host", not
  "host:abc")

Author: niemyjski

src/Foundatio.RabbitMQ/Messaging/RabbitMQMessageBus.cs

@@ -26,8 +26,8 @@ public class RabbitMQMessageBus : MessageBusBase<RabbitMQMessageBusOptions>
     private readonly List<AmqpTcpEndpoint> _endpoints;
     private IConnection? _publisherConnection;
     private IConnection? _subscriberConnection;
-    private IChannel? _publisherChannel;
-    private IChannel? _subscriberChannel;
+    private volatile IChannel? _publisherChannel;
+    private volatile IChannel? _subscriberChannel;
     private AsyncEventingBasicConsumer? _consumer;
     private bool? _delayedExchangePluginEnabled;
     private Version? _serverVersion;
@@ -94,10 +94,11 @@ protected override async Task RemoveTopicSubscriptionAsync()
     protected override async Task CleanupAsync()
     {
         _factory.AutomaticRecoveryEnabled = false;
-        _publisherReady.Set();
 
         await ClosePublisherConnectionAsync().AnyContext();
         await CloseSubscriberConnectionAsync().AnyContext();
+
+        _publisherReady.Set();
     }
 
     protected override async Task EnsureTopicSubscriptionAsync(CancellationToken cancellationToken)
@@ -865,7 +866,7 @@ private static string SanitizeUri(Uri uri)
         string hostname = trimmed[..colonIndex];
         return Int32.TryParse(trimmed[(colonIndex + 1)..], out int parsedPort)
             ? new AmqpTcpEndpoint(hostname, parsedPort)
-            : new AmqpTcpEndpoint(trimmed, defaultPort);
+            : new AmqpTcpEndpoint(hostname, defaultPort);
     }
 
     private void RegisterPublisherConnectionEventHandlers()