fix(frontend): redirect authenticated users to dashboard from landing page

- Added auth check in landing page using `useAuth`.
- Redirect authenticated users to `/dashboard`.
- Display blank screen during auth verification or redirection.

frontend/src/app/[locale]/page.tsx

@@ -3,12 +3,16 @@
  * Homepage / Landing Page
  * Main landing page for the Syndarix project
  * Showcases features, tech stack, and provides demos for developers
+ *
+ * If user is authenticated, redirects to dashboard
  */
 
 'use client';
 
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
-import { Link } from '@/lib/i18n/routing';
+import { Link, useRouter } from '@/lib/i18n/routing';
+import { useAuth } from '@/lib/auth/AuthContext';
+import config from '@/config/app.config';
 import { Header } from '@/components/home/Header';
 import { HeroSection } from '@/components/home/HeroSection';
 import { ContextSection } from '@/components/home/ContextSection';
@@ -24,6 +28,20 @@ import { DemoCredentialsModal } from '@/components/home/DemoCredentialsModal';
 
 export default function Home() {
   const [demoModalOpen, setDemoModalOpen] = useState(false);
+  const router = useRouter();
+  const { isAuthenticated, isLoading } = useAuth();
+
+  // Redirect authenticated users to dashboard
+  useEffect(() => {
+    if (!isLoading && isAuthenticated) {
+      router.push(config.routes.dashboard);
+    }
+  }, [isLoading, isAuthenticated, router]);
+
+  // Show nothing while checking auth or redirecting
+  if (isLoading || isAuthenticated) {
+    return null;
+  }
 
   return (
     <div className="min-h-screen">