Add DEMO feature to the project

frontend/src/api/hooks/subscription.ts

@@ -111,6 +111,9 @@ export const useSubscription = () => {
       const analyticsLevel = subscriptionService.getAnalyticsLevelForPlan(planKey);
       return { hasAccess: true, level: analyticsLevel };
     }
+
+    // Default fallback when plan is not recognized
+    return { hasAccess: false, level: 'none', reason: 'Unknown plan' };
   }, [subscriptionInfo.plan]);
 
   // Check if user can access specific analytics features