Refactor attachment handling in email fetching

Consolidate `WithAttachments` behavior into `MailSearchFilter` to simplify the API and reduce redundancy.

- Removed `withAttachments` parameter from `FetchEmailsAsync` in `IImapEmailService`.
- Added `WithAttachments` property to `MailSearchFilter` to control attachment inclusion.
- Removed `WithAttachments` property from `FetchEmailsQuery` as it is now encapsulated in `MailSearchFilter`.
- Updated `FetchEmailsQueryHandler` to use `MailSearchFilter` for attachment handling.
- Refactored `LimilabsImapEmailService` to use `MailSearchFilter.WithAttachments` for mapping email data.

These changes improve maintainability and clarity by centralizing attachment-related options in `MailSearchFilter`.

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

@@ -21,12 +21,6 @@ public record FetchEmailsQuery : IRequest<IEnumerable<ReceivedEmailContext>>
     /// Mail query used to filter and limit the emails retrieved.
     /// </summary>
     public MailSearchFilter Mail { get; init; } = new();
-
-    /// <summary>
-    /// When <see langword="true"/>, attachment data is included in the results; otherwise attachments are omitted.
-    /// Defaults to <see langword="false"/>.
-    /// </summary>
-    public bool WithAttachments { get; init; } = false;
 }
 
 public class FetchEmailsQueryHandler(
@@ -46,7 +40,6 @@ public class FetchEmailsQueryHandler(
         return await ImapService.FetchEmailsAsync(
             account,
             request.Mail,
-            request.WithAttachments,
             cancellationToken);
     }
 }