Handle read-only calendars

Wino.Core.Domain/Interfaces/IAccountCalendar.cs

@@ -10,6 +10,7 @@ public interface IAccountCalendar
     string TextColorHex { get; set; }
     string BackgroundColorHex { get; set; }
     bool IsPrimary { get; set; }
+    bool IsReadOnly { get; set; }
     bool IsSynchronizationEnabled { get; set; }
     Guid AccountId { get; set; }
     string RemoteCalendarId { get; set; }

Wino.Core.Domain/Interfaces/IMailDialogService.cs

@@ -16,6 +16,7 @@ namespace Wino.Core.Domain.Interfaces;
 
 public interface IMailDialogService : IDialogServiceBase
 {
+    void ShowReadOnlyCalendarMessage();
     Task<bool> ShowHardDeleteConfirmationAsync();
     Task HandleSystemFolderConfigurationDialogAsync(Guid accountId, IFolderService folderService);