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/TerminalTabs.axaml.cs

@@ -1,9 +1,56 @@
+using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Input;
+using DodoSSH.Client.Shell.ViewModels;
 
 namespace DodoSSH.Client.App.Views;
 
-/// <summary>The tab strip above the terminal.</summary>
+/// <summary>The tab strip, above every screen.</summary>
 internal sealed partial class TerminalTabs : UserControl
 {
     public TerminalTabs() => InitializeComponent();
+
+    /// <summary>
+    /// Closes a tab on a middle click.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// Wired on the tab's own template root, which is the whole answer to "and not on the strip itself".
+    /// A middle press on the background, on the sentence, or on the button that opens a connection reaches
+    /// no handler at all, because there is none there to reach. Nothing has to test what was clicked.
+    /// </para>
+    /// <para>
+    /// <b><c>PointerUpdateKind</c>, not <c>IsMiddleButtonPressed</c>.</b> The latter reports button
+    /// <em>state</em>: it is equally true for a left press made while the middle button happens to be held,
+    /// and for every press during a middle drag. The question here is which button caused this press, and
+    /// that is the one thing only <c>PointerUpdateKind</c> answers.
+    /// </para>
+    /// <para>
+    /// On press rather than on release, which is what every browser and every terminal does. Matching a
+    /// release to its press would need capture tracking, to buy the ability to change your mind about a
+    /// middle click — a gesture nobody makes by accident and nobody aborts.
+    /// </para>
+    /// </remarks>
+    private void OnTabPointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (sender is not Visual { DataContext: TerminalTabViewModel tab }
+            || DataContext is not MainWindowViewModel shell)
+        {
+            return;
+        }
+
+        if (e.GetCurrentPoint((Visual)sender).Properties.PointerUpdateKind
+            is not PointerUpdateKind.MiddleButtonPressed)
+        {
+            return;
+        }
+
+        // Handled, so the strip's ScrollViewer does not also take this as the start of a pan.
+        e.Handled = true;
+
+        // Fire-and-forget, as the host sidebar's double-tap connect is: CloseTabCommand is asynchronous —
+        // it waits for the workspace to tear the session down — and an event handler has nowhere to await
+        // it. Its failures are the workspace's to report, not this strip's.
+        shell.CloseTabCommand.Execute(tab);
+    }
 }