refactor: align frontend ownership boundaries

Close audit gaps across API drift, query policy, UI, and tests.

src/pages/register/ui/RegisterPage.tsx

@@ -1,20 +1,14 @@
-import { Paper, Stack, Title } from "@mantine/core";
 import type { FC } from "react";
 import { useTranslation } from "react-i18next";
-import { RegisterForm } from "@/features/auth";
+import { AuthPageLayout, RegisterForm } from "@/features/auth";
 
 const RegisterPage: FC = () => {
 	const { t } = useTranslation();
 
 	return (
-		<main className="auth-page">
-			<Paper className="auth-card" p="xl" radius="lg" withBorder>
-				<Stack gap="lg">
-					<Title order={1}>{t("auth.register")}</Title>
-					<RegisterForm />
-				</Stack>
-			</Paper>
-		</main>
+		<AuthPageLayout title={t("auth.register")}>
+			<RegisterForm />
+		</AuthPageLayout>
 	);
 };