Fix Top Header layout following changes in the Shadcn Sidebar;

Fix useMobile breakpoint to 1024px, to match our Tailwind convention for mobile breakpoints (lg)

packages/ui/src/hooks/use-mobile.tsx

@@ -1,6 +1,6 @@
 import * as React from 'react';
 
-const MOBILE_BREAKPOINT = 768;
+const MOBILE_BREAKPOINT = 1024;
 
 export function useIsMobile() {
   const [isMobile, setIsMobile] = React.useState<boolean | undefined>(

packages/ui/src/makerkit/navigation-config.schema.ts

@@ -37,7 +37,7 @@ const RouteGroup = z.object({
 });
 
 export const NavigationConfigSchema = z.object({
-  style: z.enum(['custom', 'sidebar', 'header']).default('sidebar'),
+  style: z.enum(['custom', 'sidebar', 'header']).default('header'),
   sidebarCollapsed: z
     .enum(['false', 'true'])
     .default('false')

packages/ui/src/makerkit/page.tsx

@@ -114,7 +114,7 @@ export function PageBody(
 
 export function PageNavigation(props: React.PropsWithChildren) {
   return (
-    <div className={'hidden flex-1 bg-inherit lg:flex'}>{props.children}</div>
+    <div className={'flex-1 bg-inherit'}>{props.children}</div>
   );
 }