Refactor ReadEmailQuery to return structured response

Updated ReadEmailQuery to return a new response type,
ReadEmailQueryResponse, which includes both email data
and metadata (e.g., LastSync). Added the Account property
to ReadEmailQuery for specifying the email account.

Refactored ReadEmailQueryHandler to:
- Use IImapEmailService to fetch LastSync metadata.
- Return ReadEmailQueryResponse instead of a collection
  of ReceivedEmailDto.

Introduced ReadEmailQueryResponse class to encapsulate
LastSync and Emails properties.

Updated EmailController to handle the new response
structure, ensuring compatibility with the updated
ReadEmailQuery and its handler.

src/core/DigitalData.MessagingService.Application/EmailReceiving/Queries/ReadEmailQuery.cs

@@ -15,7 +15,7 @@ namespace DigitalData.MessagingService.Application.EmailReceiving.Queries;
 /// <summary>
 /// Query to fetch emails from an IMAP mailbox.
 /// </summary>
-public record ReadEmailQuery : IRequest<IEnumerable<ReceivedEmailDto>>
+public record ReadEmailQuery : IRequest<ReadEmailQueryResponse>
 {
     /// <summary>
     /// Identifies the email account to use.
@@ -28,9 +28,9 @@ public record ReadEmailQuery : IRequest<IEnumerable<ReceivedEmailDto>>
     public MailSearchFilter Mail { get; init; } = new();
 }
 
-public class ReadEmailQueryHandler(IMapper Mapper, ILogger<ReadEmailQueryHandler> Logger, IRepository<EmailAccount> EmailAccountRepo, IReceivedEmailRepository MailRepo) : IRequestHandler<ReadEmailQuery, IEnumerable<ReceivedEmailDto>>
+public class ReadEmailQueryHandler(IMapper Mapper, ILogger<ReadEmailQueryHandler> Logger, IRepository<EmailAccount> EmailAccountRepo, IReceivedEmailRepository MailRepo, IImapEmailService imapEmailService) : IRequestHandler<ReadEmailQuery, ReadEmailQueryResponse>
 {
-    public async Task<IEnumerable<ReceivedEmailDto>> Handle(ReadEmailQuery request, CancellationToken cancellationToken)
+    public async Task<ReadEmailQueryResponse> Handle(ReadEmailQuery request, CancellationToken cancellationToken)
     {
         var accounts = await EmailAccountRepo.FindAsync(request.Account.Id is int id ? x => x.Id == id : x => x.Username == request.Account.Username, cancellationToken: cancellationToken);
 
@@ -45,7 +45,14 @@ public class ReadEmailQueryHandler(IMapper Mapper, ILogger<ReadEmailQueryHandler
                 $"IMAP is not configured for account '{account.Username}' (Id: {account.Id}). Set ImapServer in EmailAccounts configuration.");
 
         var mails = await MailRepo.FindAsync(request.Mail, account, cancellationToken);
-        return Mapper.Map<IEnumerable<ReceivedEmailDto>>(mails);
+
+        var lastSync = imapEmailService.GetLastImapSyncDate(account.Id, request.Mail.Folder);
+
+        return new ReadEmailQueryResponse
+        {
+            LastSync = lastSync,
+            Emails = Mapper.Map<IEnumerable<ReceivedEmailDto>>(mails)
+        };
     }
 }
 #endif

src/core/DigitalData.MessagingService.Application/EmailReceiving/Queries/ReadEmailQueryResponse.cs

@@ -0,0 +1,17 @@
+#if NET
+using DigitalData.MessagingService.Application.Common.Dto;
+
+namespace DigitalData.MessagingService.Application.EmailReceiving.Queries;
+
+/// <summary>
+/// 
+/// </summary>
+/// <param name="Emails"></param>
+/// <param name="LastSync"></param>
+public class ReadEmailQueryResponse
+{
+    public DateTime? LastSync { get; init; } = null;
+
+    public IEnumerable<ReceivedEmailDto> Emails { get; init; } = [];
+}
+#endif

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

@@ -94,22 +94,22 @@ public class EmailController(IMediator mediator) : ControllerBase
     [ProducesResponseType(StatusCodes.Status404NotFound)]
     public async Task<IActionResult> FetchEmails([FromQuery] ReadEmailQuery query, [FromQuery] OnlyFilter? only = null, CancellationToken cancellationToken = default)
     {
-        var emails = await mediator.Send(query, cancellationToken);
+        var res = await mediator.Send(query, cancellationToken);
 
-        if(!emails.Any())
+        if(!res.Emails.Any())
             return NotFound("No emails found matching the specified criteria.");
 
         if (only == OnlyFilter.HtmlBody)
         {
-            if (emails.FirstOrDefault()?.HtmlBody is string htmlBody)
+            if (res.Emails.FirstOrDefault()?.HtmlBody is string htmlBody)
                 return Content(htmlBody, "text/html");
             else
                 return NotFound();
         }
         else if (only == OnlyFilter.Uid)
-            return Ok(emails.Select(e => e.Uid).ToList());
+            return Ok(res.Emails.Select(e => e.Uid).ToList());
         else
-            return Ok(emails);
+            return Ok(res);
     }
     #endregion Receive
 }