Start working on settings UI

SettingsWindow/GeneralSettingsPanel.xaml.cs

@@ -0,0 +1,36 @@
+using ChrisKaczor.Wpf.Application;
+using System.Windows;
+using WorldClockStatusWindow.Properties;
+
+namespace WorldClockStatusWindow.SettingsWindow;
+
+public partial class GeneralSettingsPanel
+{
+    public GeneralSettingsPanel()
+    {
+        InitializeComponent();
+    }
+
+    public override string CategoryName => Properties.Resources.optionCategoryGeneral;
+
+    public override void LoadPanel(Window parentWindow)
+    {
+        base.LoadPanel(parentWindow);
+
+        MarkLoaded();
+    }
+
+    private void OnSaveSettings(object sender, RoutedEventArgs e)
+    {
+        SaveSettings();
+    }
+
+    private void SaveSettings()
+    {
+        if (!HasLoaded) return;
+
+        Settings.Default.Save();
+
+        Application.Current.SetStartWithWindows(Settings.Default.AutoStart);
+    }
+}