fix(runtime): late top-level/instance vars used with ??= (mediaQuery/screenHeight/etc) -> nullable. Fixes LateInitializationError on /me /shop /product-detail

lib/widgets/desktop/desktop_me.dart

@@ -16,9 +16,9 @@ import '../../utils/util_web.dart'
     if (dart.library.io) '../../utils/util_io.dart';
 import '../../utils/utils.dart';
 
-late MediaQueryData mediaQuery;
-late double statusBarHeight;
-late double screenHeight;
+MediaQueryData? mediaQuery;
+double? statusBarHeight;
+double? screenHeight;
 
 class DesktopMe extends StatefulWidget {
   final Key? key;
@@ -67,8 +67,8 @@ class DesktopMeState extends State<DesktopMe> {
     }
 
     mediaQuery ??= MediaQuery.of(context);
-    screenHeight ??= mediaQuery.size.height;
-    statusBarHeight ??= mediaQuery.padding.top;
+    screenHeight ??= mediaQuery!.size.height;
+    statusBarHeight ??= mediaQuery!.padding.top;
 
     Widget userInfo = GestureDetector(
       child: Container(