feat: system settings stored as applets in virtual folder

programs/include/gui/desktop.hpp

@@ -131,6 +131,9 @@ struct DesktopState {
     SvgIcon icon_home_folder_lg;
     SvgIcon icon_apps;
     SvgIcon icon_apps_lg;
+    SvgIcon icon_system_tools_menu;
+    SvgIcon icon_system_tools;
+    SvgIcon icon_system_tools_lg;
 
     // Special user folder icons (16x16 and 48x48)
     static constexpr int SPECIAL_FOLDER_COUNT = 6;