Desktop: put the keyboard in the closed vault's card on launch, and let Enter sign in and enrol

src/DodoSSH.Client.App/Views/MainWindow.axaml.cs

@@ -33,6 +33,9 @@ internal sealed partial class MainWindow : Window
 
     private bool wasUnlocked;
 
+    /// <summary>Which closed-vault card the keyboard was last sent to, so it is sent once per card.</summary>
+    private ShellState? closedState;
+
     public MainWindow()
     {
         InitializeComponent();
@@ -184,6 +187,7 @@ internal sealed partial class MainWindow : Window
     {
         ShellState.Locked => UnlockPane.PassphraseBox,
         ShellState.NeedsServer => ServerUrlBox,
+        ShellState.NeedsEnrollment => NewPassphraseBox,
         _ => this,
     };
 
@@ -307,6 +311,14 @@ internal sealed partial class MainWindow : Window
         Terminal.Source = viewModel.TerminalPageUrl;
 
         wasUnlocked = viewModel.IsUnlocked;
+        closedState = null;
+
+        // The shell may have reached its card before this window was given it, and then no change would
+        // ever say so.
+        if (!viewModel.IsUnlocked)
+        {
+            FocusClosedVaultCard(viewModel);
+        }
 
         viewModel.TerminalSessionOpened += OnTerminalSessionOpened;
         viewModel.TerminalFocusRequested += OnTerminalFocusRequested;
@@ -380,10 +392,32 @@ internal sealed partial class MainWindow : Window
         {
             ReleaseKeyboardTo(ClosedVaultKeyboardHome);
         }
+        else if (!unlocked && viewModel.State != closedState)
+        {
+            FocusClosedVaultCard(viewModel);
+        }
 
+        closedState = unlocked ? null : viewModel.State;
         wasUnlocked = unlocked;
     }
 
+    /// <summary>Hands the keyboard to the box on whichever card a closed vault is showing.</summary>
+    /// <remarks>
+    /// For arriving at a card other than by locking — launch landing on the unlock card, a sign-in finishing
+    /// on the enrolment one — which used to leave the passphrase somebody started typing going nowhere. Once
+    /// per card, which is what keeps it from moving the keyboard while somebody is mid-sign-in: IsUnlocked is
+    /// raised for every state change, and the state does not change while they type. Posted, because the card
+    /// is revealed by a binding the same change has not reached yet.
+    /// </remarks>
+    private void FocusClosedVaultCard(MainWindowViewModel viewModel)
+    {
+        closedState = viewModel.State;
+
+        var home = ClosedVaultKeyboardHome;
+
+        Dispatcher.UIThread.Post(() => home.Focus(), DispatcherPriority.Loaded);
+    }
+
     /// <remarks>
     /// Closing only. Opening also has to move the keyboard — the palette is a text box somebody is expected
     /// to start typing into immediately — but the palette does that for itself when it becomes visible,