fix: enforce semantic contrast across admin

src/app/admin/applications/page.tsx

@@ -89,7 +89,7 @@ export default async function AdminApplications() {
                       {t("rankLabel", { rank: a.rankId })}
                     </span>
                   </div>
-                  <p className="text-xs text-gray-500 dark:text-gray-400 m-0 mb-2">
+                  <p className="text-xs theme-text-muted dark:theme-text-muted m-0 mb-2">
                     {formatDate(a.createdAt)}
                   </p>
                   <p className="text-sm text-[var(--color-text)] whitespace-pre-wrap m-0 mb-3">{a.content}</p>