fix: move useState hook before conditional return in profile page

The activeTab useState was called after the if(loading) return, violating
React's Rules of Hooks and causing error #310 at runtime.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/app/dashboard/profile/page.tsx

@@ -71,6 +71,7 @@ export default function ProfilePage() {
   const [loadingPortal, setLoadingPortal] = useState(false);
   const [loadingCancel, setLoadingCancel] = useState(false);
   const [isClearing, setIsClearing] = useState(false);
+  const [activeTab, setActiveTab] = useState('account');
   const [defaultLanguage, setDefaultLanguage] = useState(settings.defaultTargetLanguage);
 
   const token = typeof window !== 'undefined' ? localStorage.getItem('token') : null;
@@ -162,9 +163,6 @@ export default function ProfilePage() {
   const docsPct = pct(docsUsed, docsLimit);
   const pagesPct = pct(pagesUsed, pagesLimit);
 
-  // Tab state for editorial pill toggle
-  const [activeTab, setActiveTab] = useState('account');
-
   return (
     <div className="flex h-full flex-col overflow-y-auto">
       <div className="flex flex-1 flex-col gap-8 p-6 lg:p-8 max-w-4xl mx-auto w-full">