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/Common/Interfaces/IImapEmailService.cs

@@ -13,12 +13,10 @@ public interface IImapEmailService
     /// </summary>
     /// <param name="account">Account whose IMAP settings will be used.</param>
     /// <param name="filter">Filter to apply when fetching emails.</param>
-    /// <param name="withAttachments">When <see langword="true"/>, attachment data is included in the results; otherwise attachments are omitted. Defaults to <see langword="false"/>.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     Task<IEnumerable<ReceivedEmailContext>> FetchEmailsAsync(
         EmailAccountDto account,
         MailSearchFilter filter,
-        bool withAttachments = false,
         CancellationToken cancellationToken = default);
 
     /// <summary>

src/core/DigitalData.MessagingService.Application/Common/Models/MailSearch/MailSearchFilter.cs

@@ -25,6 +25,12 @@ public record MailSearchFilter
     /// </summary>
     public bool HasAttachments { get; init; } = false;
 
+    /// <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;
+
     /// <summary>
     /// Maximum number of messages to retrieve. <c>0</c> means unlimited.
     /// Applied after sorting; defaults to <c>50</c>.

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);
     }
 }

src/infrastructure/DigitalData.MessagingService.Infrastructure/Services/LimilabsImapEmailService.cs

@@ -27,7 +27,6 @@ public class LimilabsImapEmailService(
     public async Task<IEnumerable<ReceivedEmailContext>> FetchEmailsAsync(
         EmailAccountDto account,
         MailSearchFilter filter,
-        bool withAttachments = false,
         CancellationToken cancellationToken = default)
     {
         using var imap = new Imap();
@@ -104,7 +103,7 @@ public class LimilabsImapEmailService(
                     if (filter.HasAttachments && mail.Attachments.Count == 0 && mail.Visuals.Count == 0)
                         continue;
 
-                    results.Add(MapToContext(uid, mail, flags, withAttachments));
+                    results.Add(MapToContext(uid, mail, flags, filter.WithAttachments));
                 }
                 catch (Exception ex)
                 {