Fixing UI thread issues with bulk operations and request queue refactoring.

Wino.Core/Requests/Mail/DeleteRequest.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using CommunityToolkit.Mvvm.Messaging;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Enums;
@@ -19,6 +20,7 @@ public record DeleteRequest(MailCopy MailItem) : MailRequestBase(MailItem),
     public List<Guid> SynchronizationFolderIds => [Item.FolderId];
     public bool ExcludeMustHaveFolders => false;
     public override MailSynchronizerOperation Operation => MailSynchronizerOperation.Delete;
+    public override object GroupingKey() => (Operation, Item.FolderId);
 
     public override void ApplyUIChanges()
     {
@@ -36,4 +38,22 @@ public class BatchDeleteRequest : BatchCollection<DeleteRequest>
     public BatchDeleteRequest(IEnumerable<DeleteRequest> collection) : base(collection)
     {
     }
+
+    public override void ApplyUIChanges()
+    {
+        var removedMails = this.Select(x => x.Item).Where(x => x != null).ToList();
+        if (removedMails.Count == 0)
+            return;
+
+        WeakReferenceMessenger.Default.Send(new BulkMailRemovedMessage(removedMails, EntityUpdateSource.ClientUpdated));
+    }
+
+    public override void RevertUIChanges()
+    {
+        var addedMails = this.Select(x => x.Item).Where(x => x != null).ToList();
+        if (addedMails.Count == 0)
+            return;
+
+        WeakReferenceMessenger.Default.Send(new BulkMailAddedMessage(addedMails, EntityUpdateSource.ClientReverted));
+    }
 }