Refactor header and layout components, remove About page, and introduce Background component for improved UI structure

apps/frontend/src/routes/__root.tsx

@@ -1,3 +1,4 @@
+import { Background } from '@/components/background';
 import { Layout } from '@/components/layout';
 import { NotFoundPage } from '@/features/not-found/not-found-page';
 import { ServerErrorPage } from '@/features/server-error/server-error-page';
@@ -16,14 +17,27 @@ export const Route = createRootRouteWithContext<RouterContext>()({
   notFoundComponent: NotFoundPage,
 });
 
+const AUTH_PAGE_REGEX =
+  /^\/(login|select-complex|reset-password|onboard|invite|auth-callback)(?:\/|$)/;
+
 function RootRoute() {
   const location = useLocation();
   const isPublicBookingRoute = /^\/[^/]+\/booking(?:\/|$)/.test(location.pathname);
+  const isAuthPage = AUTH_PAGE_REGEX.test(location.pathname);
 
   if (isPublicBookingRoute) {
     return <Outlet />;
   }
 
+  if (isAuthPage) {
+    return (
+      <div className="relative min-h-dvh overflow-x-hidden bg-background text-foreground">
+        <Background />
+        <Outlet />
+      </div>
+    );
+  }
+
   return (
     <Layout>
       <div className="flex flex-col">