feat: add loader for initial snapshot in notification scene

Mastodon/Scene/Notification/NotificationViewModel+diffable.swift

@@ -29,6 +29,14 @@ extension NotificationViewModel {
             delegate: delegate,
             dependency: dependency
         )
+
+        var snapshot = NSDiffableDataSourceSnapshot<NotificationSection, NotificationItem>()
+        snapshot.appendSections([.main])
+        diffableDataSource.apply(snapshot)
+
+        // workaround to append loader wrong animation issue
+        snapshot.appendItems([.bottomLoader], toSection: .main)
+        diffableDataSource.apply(snapshot)
     }
 }
 

Mastodon/Scene/Notification/NotificationViewModel.swift

@@ -35,6 +35,7 @@ final class NotificationViewModel: NSObject {
     
     // output
     var diffableDataSource: UITableViewDiffableDataSource<NotificationSection, NotificationItem>!
+    
     // top loader
     private(set) lazy var loadLatestStateMachine: GKStateMachine = {
         // exclude timeline middle fetcher state