Merge branch 'main' into the Android head

Main grew the screens the host-management plan called for — hosts, pins, snippets, logs,
import, teams — plus the ObjectStore and Import projects behind two of them, and moved
WindowsDeviceKeyStore into the desktop head's Platform folder.

Five of those view models landed in a directory this branch had already moved, so they
join the rest in DodoSSH.Client.Shell: git spotted the rename and put them there, and the
namespaces followed. Shell picks up ObjectStore and Import as a result, which the Android
head then gets transitively and will use neither of at first — scoped storage means there
is no ~/.ssh/config to import, and file transfer is out of its first scope.

Desktop suites green at 155 and 64.

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

@@ -0,0 +1,37 @@
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using DodoSSH.Client.Shell.ViewModels;
+
+namespace DodoSSH.Client.App.Views;
+
+/// <summary>
+/// Importing hosts from <c>~/.ssh/config</c>.
+/// </summary>
+/// <remarks>
+/// A task rather than a destination, which is why it is reached from preferences and not from the nav rail.
+/// </remarks>
+internal sealed partial class ImportScreen : UserControl
+{
+    public ImportScreen()
+    {
+        InitializeComponent();
+
+        // The count on the import button is derived from the ticks, and a CheckBox bound with
+        // {Binding IsSelected} tells its own row and nothing else. Rather than have every row hold a
+        // reference back to the screen, the screen listens for the event they all bubble.
+        AddHandler(ToggleButton.IsCheckedChangedEvent, OnTickChanged, RoutingStrategies.Bubble);
+    }
+
+    /// <summary>Where the keyboard lands when this screen is the one showing.</summary>
+    internal IInputElement KeyboardTarget => this;
+
+    private void OnTickChanged(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is ImportViewModel import)
+        {
+            import.NoteSelectionChanged();
+        }
+    }
+}