Add routing menu to Desktop tray icon

Add routing selection functionality to the system tray menu for
macOS/Linux (Avalonia Desktop), bringing feature parity with the
Windows version which already has this capability.

- Add dynamic routing items to NativeMenu in App.axaml
- Implement menu item click handling and state refresh in App.axaml.cs
- Support radio-style selection for routing options

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

v2rayN/v2rayN.Desktop/App.axaml

@@ -64,6 +64,14 @@
                             IsVisible="{Binding BlSystemProxyPacVisible}"
                             ToggleType="Radio" />
                         <NativeMenuItemSeparator />
+                        <NativeMenuItem
+                            Header="{x:Static resx:ResUI.menuRouting}"
+                            IsVisible="{Binding BlRouting}">
+                            <NativeMenuItem.Menu>
+                                <NativeMenu />
+                            </NativeMenuItem.Menu>
+                        </NativeMenuItem>
+                        <NativeMenuItemSeparator />
                         <NativeMenuItem Click="MenuAddServerViaClipboardClick" Header="{x:Static resx:ResUI.menuAddServerViaClipboard}" />
                         <NativeMenuItem Command="{Binding SubUpdateCmd}" Header="{x:Static resx:ResUI.menuSubUpdate}" />
                         <NativeMenuItem Command="{Binding SubUpdateViaProxyCmd}" Header="{x:Static resx:ResUI.menuSubUpdateViaProxy}" />

v2rayN/v2rayN.Desktop/App.axaml.cs

@@ -4,6 +4,8 @@ namespace v2rayN.Desktop;
 
 public partial class App : Application
 {
+    private readonly Dictionary<NativeMenuItem, string> _routingMenuMap = [];
+
     public override void Initialize()
     {
         AvaloniaXamlLoader.Load(this);
@@ -20,6 +22,7 @@ public partial class App : Application
             {
                 AppManager.Instance.InitComponents();
                 DataContext = StatusBarViewModel.Instance;
+                InitRoutingMenu();
             }
 
             desktop.Exit += OnExit;
@@ -44,6 +47,118 @@ public partial class App : Application
 
     private void OnExit(object? sender, ControlledApplicationLifetimeExitEventArgs e)
     {
+        foreach (var menuItem in _routingMenuMap.Keys)
+        {
+            menuItem.Click -= MenuRoutingClick;
+        }
+        _routingMenuMap.Clear();
+    }
+
+    private void InitRoutingMenu()
+    {
+        var vm = StatusBarViewModel.Instance;
+        vm.RoutingItems.CollectionChanged += (_, _) => RefreshRoutingMenuItems();
+        vm.PropertyChanged += (_, args) =>
+        {
+            if (args.PropertyName == nameof(StatusBarViewModel.SelectedRouting))
+            {
+                RefreshRoutingMenuCheckState();
+            }
+        };
+
+        RefreshRoutingMenuItems();
+    }
+
+    private void RefreshRoutingMenuItems()
+    {
+        Dispatcher.UIThread.Post(() =>
+        {
+            var routingMenu = GetRoutingRootMenu();
+            if (routingMenu == null)
+            {
+                return;
+            }
+
+            routingMenu.Menu ??= new NativeMenu();
+            foreach (var menuItem in _routingMenuMap.Keys)
+            {
+                menuItem.Click -= MenuRoutingClick;
+            }
+            _routingMenuMap.Clear();
+            routingMenu.Menu.Items.Clear();
+
+            foreach (var routing in StatusBarViewModel.Instance.RoutingItems)
+            {
+                var menuItem = new NativeMenuItem
+                {
+                    Header = routing.Remarks,
+                    IsChecked = routing.IsActive,
+                    ToggleType = NativeMenuItemToggleType.Radio,
+                };
+                menuItem.Click += MenuRoutingClick;
+                _routingMenuMap[menuItem] = routing.Id;
+                routingMenu.Menu.Items.Add(menuItem);
+            }
+
+            RefreshRoutingMenuCheckState();
+        }, DispatcherPriority.Background);
+    }
+
+    private void RefreshRoutingMenuCheckState()
+    {
+        Dispatcher.UIThread.Post(() =>
+        {
+            var selectedRoutingId = StatusBarViewModel.Instance.SelectedRouting?.Id;
+            foreach (var pair in _routingMenuMap)
+            {
+                pair.Key.IsChecked = pair.Value == selectedRoutingId;
+            }
+        }, DispatcherPriority.Background);
+    }
+
+    private NativeMenuItem? GetRoutingRootMenu()
+    {
+        if (Current == null)
+        {
+            return null;
+        }
+
+        var icons = TrayIcon.GetIcons(Current);
+        if (icons.Count == 0 || icons[0].Menu is not NativeMenu trayMenu)
+        {
+            return null;
+        }
+
+        return trayMenu.Items
+            .OfType<NativeMenuItem>()
+            .FirstOrDefault(x => Equals(x.Header, ResUI.menuRouting));
+    }
+
+    private void MenuRoutingClick(object? sender, EventArgs e)
+    {
+        if (sender is not NativeMenuItem menuItem)
+        {
+            return;
+        }
+
+        if (!_routingMenuMap.TryGetValue(menuItem, out var routingId))
+        {
+            return;
+        }
+
+        var target = StatusBarViewModel.Instance.RoutingItems.FirstOrDefault(x => x.Id == routingId);
+        if (target == null)
+        {
+            return;
+        }
+
+        if (StatusBarViewModel.Instance.SelectedRouting?.Id == target.Id)
+        {
+            RefreshRoutingMenuCheckState();
+            return;
+        }
+
+        StatusBarViewModel.Instance.SelectedRouting = target;
     }
 
     private async void MenuAddServerViaClipboardClick(object? sender, EventArgs e)