feat: add ReplyTo to CorrelationContext

- Allows message publishers to specify a reply queue
- Consumer publishes result to ReplyTo queue if set
- If ReplyTo is null, behavior is fire-and-forget

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Hrynco.RabbitMq/CorrelationContext.cs

@@ -3,4 +3,11 @@ namespace Hrynco.RabbitMq;
 public record CorrelationContext
 {
     public required string CorrelationId { get; init; }
+
+    /// <summary>
+    /// Optional queue name the sender wants the result published to.
+    /// If set, the consumer should publish a result message to this queue after processing.
+    /// If null, the sender does not require a reply (fire-and-forget).
+    /// </summary>
+    public string? ReplyTo { get; init; }
 }