Listing account calendars on the shell, some visual state updates and reacting to calendar setting changes properly.

Wino.Calendar/Services/AccountCalendarStateService.cs

@@ -0,0 +1,13 @@
+using System.Collections.ObjectModel;
+using CommunityToolkit.Mvvm.ComponentModel;
+using Wino.Calendar.ViewModels.Data;
+using Wino.Calendar.ViewModels.Interfaces;
+
+namespace Wino.Calendar.Services
+{
+    public partial class AccountCalendarStateService : ObservableObject, IAccountCalendarStateService
+    {
+        [ObservableProperty]
+        private ObservableCollection<GroupedAccountCalendarViewModel> _groupedAccountCalendars = new ObservableCollection<GroupedAccountCalendarViewModel>();
+    }
+}