Make OutgoingEmailConsumer more robust and maintainable

- Added null-safety checks (`?.`) for `ILogger` usage in `OutgoingEmailConsumer`.
- Removed unused `AsyncEventingBasicConsumer` and `_lazyInit` fields.
- Updated `DisposeAsync` to check `_lazyChannel.IsValueCreated` before accessing it.
- Added infinite delay in `AsyncInitWorker` to keep the background service active until cancellation.
- Improved overall maintainability and reduced potential runtime issues.

src/DigitalData.MessagingService.Infrastructure/Queue/OutgoingEmailConsumer.cs

@@ -21,8 +21,6 @@ public sealed class OutgoingEmailConsumer : IAsyncDisposable
 
     private readonly Lazy<Task<IChannel>> _lazyChannel;
 
-    private readonly AsyncEventingBasicConsumer? consumer;
-
     private readonly Lazy<Task> _lazyInit;
 
     private readonly ILogger<OutgoingEmailConsumer>? _logger;
@@ -60,13 +58,13 @@ public sealed class OutgoingEmailConsumer : IAsyncDisposable
                     }
                     else
                     {
-                        logger.LogWarning("Failed to deserialize email message: DeliveryTag={DeliveryTag}", args.DeliveryTag);
+                        logger?.LogWarning("Failed to deserialize email message: DeliveryTag={DeliveryTag}", args.DeliveryTag);
                         await channel.BasicNackAsync(args.DeliveryTag, false, false, args.CancellationToken); // Don't requeue invalid messages
                     }
                 }
                 catch (Exception ex)
                 {
-                    logger.LogError(ex, "Failed to process email [To={To}, Subject={Subject}] message: DeliveryTag={DeliveryTag}. Moving to DLQ (NO retry).", oMailEvent?.Recipient, oMailEvent?.Subject, args.DeliveryTag);
+                    logger?.LogError(ex, "Failed to process email [To={To}, Subject={Subject}] message: DeliveryTag={DeliveryTag}. Moving to DLQ (NO retry).", oMailEvent?.Recipient, oMailEvent?.Subject, args.DeliveryTag);
 
                     // TODO: Error Reporting Strategy
                     // Option 1: Separate RabbitMQ Queue (emailprofiler.errors)
@@ -100,7 +98,7 @@ public sealed class OutgoingEmailConsumer : IAsyncDisposable
                 consumer: consumer,
                 cancellationToken: CnnFactory.CancellationToken);
 
-            logger.LogInformation("RabbitMQ consumer started for queue: {QueueName}", _config.QueueName);
+            logger?.LogInformation("RabbitMQ consumer started for queue: {QueueName}", _config.QueueName);
         });
     }
 
@@ -119,6 +117,9 @@ public sealed class OutgoingEmailConsumer : IAsyncDisposable
 
     public async ValueTask DisposeAsync()
     {
+        if (!_lazyChannel.IsValueCreated)
+            return;
+
         var channel = await _lazyChannel.Value;
         if (channel is not null)
         {

src/DigitalData.MessagingService.Infrastructure/Services/Background/AsyncInitWorker.cs

@@ -14,5 +14,7 @@ public class AsyncInitWorker(OutgoingEmailConsumer EmailConsumer) : BackgroundSe
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
         await EmailConsumer.InitAsync();
+
+        await Task.Delay(Timeout.Infinite, stoppingToken).ConfigureAwait(ConfigureAwaitOptions.SuppressThrowing);
     }
 }