auto-claude: subtask-2-1 - Simplify DashboardContent client-side auth check

Removed redundant client-side redirect logic from DashboardContent since
server-side middleware now handles route protection (Phase 1 complete).

Changes:
- Removed redirect to login page from useEffect (now handled by middleware)
- Renamed checkAuth to fetchUser (more accurate purpose)
- Removed locale and router from useEffect dependencies (no longer needed)
- Kept loading state and user fetching for display purposes
- Component now trusts middleware protection and focuses on data display

The component still:
- Fetches user data for display (email, etc.)
- Shows loading state during fetch
- Handles logout functionality
- Maintains existing UI/UX

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/components/auth/DashboardContent.tsx

@@ -24,21 +24,16 @@ export default function DashboardContent() {
   const [loading, setLoading] = useState(true);
 
   useEffect(() => {
-    const checkAuth = async () => {
+    const fetchUser = async () => {
       const supabase = createClient();
       const { data: { user } } = await supabase.auth.getUser();
 
-      if (!user) {
-        router.push(`/${locale}/login`);
-        return;
-      }
-
       setUser(user);
       setLoading(false);
     };
 
-    checkAuth();
-  }, [locale, router]);
+    fetchUser();
+  }, []);
 
   const handleLogout = async () => {
     const supabase = createClient();