Apply code review

Author: d2dyno1

src/Sdk/SecureFolderFS.Sdk/ViewModels/Views/Credentials/CredentialsSelectionViewModel.cs

@@ -1,4 +1,9 @@
-using CommunityToolkit.Mvvm.ComponentModel;
+using System;
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Threading;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using OwlCore.Storage;
 using SecureFolderFS.Sdk.Attributes;
@@ -9,12 +14,6 @@
 using SecureFolderFS.Shared;
 using SecureFolderFS.Shared.ComponentModel;
 using SecureFolderFS.Shared.Extensions;
-using System;
-using System.Collections.ObjectModel;
-using System.ComponentModel;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SecureFolderFS.Shared.Models;
 
 namespace SecureFolderFS.Sdk.ViewModels.Views.Credentials

src/Sdk/SecureFolderFS.Sdk/ViewModels/Views/Overlays/CredentialsOverlayViewModel.cs

@@ -99,8 +99,9 @@ private void LoginViewModel_VaultUnlocked(object? sender, VaultUnlockedEventArgs
 
                 // Seed the register sequence with the already-authenticated first-stage key
                 // so that when a second-stage method is added, the combined passkey is complete
-                foreach (var key in _loginKeySequence.Keys)
-                    _registerKeySequence.SetOrAdd(0, key); // First-stage lives at index 0
+                var firstStageKey = _loginKeySequence.Keys.FirstOrDefault();
+                if (firstStageKey is not null)
+                    _registerKeySequence.SetOrAdd(0, firstStageKey); // First-stage lives at index 0
 
                 SelectionViewModel.RegisterViewModel = RegisterViewModel;
                 SelectedViewModel = SelectionViewModel;
@@ -130,6 +131,7 @@ public void Dispose()
             (SelectedViewModel as IDisposable)?.Dispose();
             SelectionViewModel.Dispose();
             LoginViewModel.Dispose();
+            RegisterViewModel.Dispose();
             _loginKeySequence.Dispose();
             _registerKeySequence.Dispose();
         }