Add config import and export

MainWindow.xaml.cs

@@ -636,6 +636,77 @@ public partial class MainWindow : Window
         }
     }
 
+    private void ExportConfig_Click(object sender, RoutedEventArgs e)
+    {
+        if (controller is null)
+        {
+            return;
+        }
+
+        ApplyConfigFields();
+        using SaveFileDialog dialog = new()
+        {
+            Title = "Export launcher config",
+            Filter = "JSON config files|*.json|All files|*.*",
+            FileName = $"TaskbarLauncher-config-{DateTime.Now:yyyyMMdd-HHmmss}.json",
+            InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
+        };
+
+        if (dialog.ShowDialog() != System.Windows.Forms.DialogResult.OK)
+        {
+            return;
+        }
+
+        try
+        {
+            string exportPath = ConfigService.ExportTo(dialog.FileName, controller.Config);
+            StatusText.Text = $"Exported config to {exportPath}";
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show($"Could not export config.\n\n{ex.Message}", "Taskbar Launcher");
+        }
+    }
+
+    private void ImportConfig_Click(object sender, RoutedEventArgs e)
+    {
+        using OpenFileDialog dialog = new()
+        {
+            Title = "Import launcher config",
+            Filter = "JSON config files|*.json|All files|*.*",
+            InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
+        };
+
+        if (dialog.ShowDialog() != System.Windows.Forms.DialogResult.OK)
+        {
+            return;
+        }
+
+        MessageBoxResult result = MessageBox.Show(
+            "Import this config file and replace the current launcher config?\n\nA local backup will be created first.",
+            "Taskbar Launcher",
+            MessageBoxButton.YesNo,
+            MessageBoxImage.Question);
+
+        if (result != MessageBoxResult.Yes)
+        {
+            return;
+        }
+
+        try
+        {
+            string backupPath = ConfigService.Backup();
+            ConfigService.ImportFrom(dialog.FileName);
+            controller?.ReloadConfig();
+            RefreshView();
+            StatusText.Text = $"Imported config from {dialog.FileName}. Previous config backed up to {backupPath}";
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show($"Could not import config.\n\n{ex.Message}", "Taskbar Launcher");
+        }
+    }
+
     private List<int>? FindItemPath(LauncherItem item)
     {
         if (controller is null)