Rename SendEmailCommand to PublishEmailCommand

Refactor the codebase to rename `SendEmailCommand` and its associated components to `PublishEmailCommand` for improved clarity and consistency.

- Updated mapping in `EmailMappingProfile.cs` to use `PublishEmailCommand` instead of `SendEmailCommand`.
- Renamed `SendEmailCommand` to `PublishEmailCommand` in `PublishEmailCommand.cs`, including its methods like `WithAttachments`.
- Renamed `SendEmailCommandHandler` to `PublishEmailCommandHandler` and updated its method signature to handle the new command.
- Renamed `SendEmailCommandValidator` to `PublishEmailCommandValidator` and updated validation rules accordingly.
- Updated the `SendEmail` action in `EmailsController.cs` to accept `PublishEmailCommand` instead of `SendEmailCommand`.

These changes ensure consistency across the codebase and better reflect the purpose of the command.

src/core/DigitalData.MessagingService.Application/Common/Mappings/EmailMappingProfile.cs

@@ -11,9 +11,9 @@ public class EmailMappingProfile : Profile
 {
     public EmailMappingProfile()
     {
-        // SendEmailCommand -> Email
+        // PublishEmailCommand -> Email
         // Sender is resolved via MediatR in the handler and set separately after mapping.
-        CreateMap<SendEmailCommand, EmailContext>()
+        CreateMap<PublishEmailCommand, EmailContext>()
             .ForMember(dest => dest.Sender, opt => opt.Ignore())
             .ForMember(dest => dest.Attachments, opt => opt.MapFrom(src => src.Attachments));
     }

src/core/DigitalData.MessagingService.Application/EmailSending/Commands/PublishEmailCommand.cs

@@ -10,7 +10,7 @@ namespace DigitalData.MessagingService.Application.EmailSending.Commands;
 /// <summary>
 /// Command to send an email (enqueue to RabbitMQ)
 /// </summary>
-public record SendEmailCommand : IRequest<Guid>
+public record PublishEmailCommand : IRequest<Guid>
 {
     public required GetSenderQuery Sender { get; init; }
 
@@ -41,17 +41,17 @@ public record SendEmailCommand : IRequest<Guid>
     /// Returns a new command instance with the supplied attachments.
     /// Called by the controller after resolving uploaded files.
     /// </summary>
-    public SendEmailCommand WithAttachments(IEnumerable<EmailAttachmentContext> attachments)
+    public PublishEmailCommand WithAttachments(IEnumerable<EmailAttachmentContext> attachments)
         => this with { Attachments = attachments };
 }
 
 /// <summary>
-/// Handler for SendEmailCommand
+/// Handler for PublishEmailCommand
 /// Resolves the sender account via MediatR, maps to SendingEmailEvent and enqueues to RabbitMQ
 /// </summary>
-public class SendEmailCommandHandler(ISender Sender, ISendingEmailPublisher Publisher, IMapper Mapper) : IRequestHandler<SendEmailCommand, Guid>
+public class PublishEmailCommandHandler(ISender Sender, ISendingEmailPublisher Publisher, IMapper Mapper) : IRequestHandler<PublishEmailCommand, Guid>
 {
-    public async Task<Guid> Handle(SendEmailCommand request, CancellationToken cancellationToken)
+    public async Task<Guid> Handle(PublishEmailCommand request, CancellationToken cancellationToken)
     {
         var senderAccount = await Sender.Send(request.Sender, cancellationToken)
             ?? throw new NotFoundException(

src/core/DigitalData.MessagingService.Application/EmailSending/Validators/SendEmailCommandValidator.cs

@@ -4,11 +4,11 @@ using FluentValidation;
 namespace DigitalData.MessagingService.Application.EmailSending.Validators;
 
 /// <summary>
-/// Validator for SendEmailCommand
+/// Validator for PublishEmailCommand
 /// </summary>
-public class SendEmailCommandValidator : AbstractValidator<SendEmailCommand>
+public class PublishEmailCommandValidator : AbstractValidator<PublishEmailCommand>
 {
-    public SendEmailCommandValidator()
+    public PublishEmailCommandValidator()
     {
         RuleFor(x => x.Recipients)
             .NotEmpty()

src/presentation/DigitalData.MessagingService.API/Controllers/EmailsController.cs

@@ -26,7 +26,7 @@ public class EmailsController(IMediator mediator) : ControllerBase
     [ProducesResponseType(StatusCodes.Status202Accepted)]
     [ProducesResponseType(StatusCodes.Status400BadRequest)]
     public async Task<IActionResult> SendEmail(
-        [FromForm] SendEmailCommand command,
+        [FromForm] PublishEmailCommand command,
         IFormFileCollection? attachments,
         CancellationToken cancellationToken)
     {