fix: enforce semantic contrast across admin

src/app/admin/media/page.tsx

@@ -18,7 +18,7 @@ export default async function AdminMediaPage() {
         </div>
         <Link
           href="/admin/articles"
-          className="text-sm text-gray-500 dark:text-gray-400"
+          className="text-sm theme-text-muted dark:theme-text-muted"
           style={{ fontSize: "0.88rem" }}
         >
           ← {t("articles")}