Refactor email handling for improved structure

Refactored `Email` and `SendingEmailEvent` to use `record` types, consolidating email-related data into the `Email` class. Updated `SendEmailCommand` to return a `Guid` and simplified mapping logic in `EmailMappingProfile`. Adjusted `SendEmailCommandHandler` to construct `SendingEmailEvent` manually.

Updated `SendingEmailConsumer`, `EmailsController`, and `EmailSender` to reflect the new structure. Removed the old `Email` implementation. Improved logging to reference the `Mail` property.

Revised tests to align with the new structure, ensuring immutability and better separation of concerns.

src/infrastructure/DigitalData.MessagingService.Infrastructure/Queue/SendingEmailConsumer.cs

@@ -48,11 +48,11 @@ public sealed class SendingEmailConsumer : IAsyncDisposable
                     {
                         // Send email via SMTP (SMTP config is injected in IEmailService via IOptions)
                         await EmailService.SendEmailAsync(
-                            oMailEvent.Sender,
-                            oMailEvent.Recipients,
-                            oMailEvent.Subject,
-                            oMailEvent.Body,
-                            isHtml: oMailEvent.IsHtml);
+                            oMailEvent.Mail.Sender,
+                            oMailEvent.Mail.Recipients,
+                            oMailEvent.Mail.Subject,
+                            oMailEvent.Mail.Body,
+                            isHtml: oMailEvent.Mail.IsHtml);
 
                         // Acknowledge message after successful processing
                         await channel.BasicAckAsync(args.DeliveryTag, false, args.CancellationToken);
@@ -65,7 +65,7 @@ public sealed class SendingEmailConsumer : IAsyncDisposable
                 }
                 catch (Exception ex)
                 {
-                    logger?.LogError(ex, "Failed to process email [To={To}, Subject={Subject}] message: DeliveryTag={DeliveryTag}. Moving to DLQ (NO retry).", oMailEvent?.Recipients, oMailEvent?.Subject, args.DeliveryTag);
+                    logger?.LogError(ex, "Failed to process email [To={To}, Subject={Subject}] message: DeliveryTag={DeliveryTag}. Moving to DLQ (NO retry).", oMailEvent?.Mail.Recipients, oMailEvent?.Mail.Subject, args.DeliveryTag);
 
                     // TODO: Error Reporting Strategy
                     // Option 1: Separate RabbitMQ Queue (emailprofiler.errors)