Fix demo session exit redirecting to unauthorized page

Clear auth store when exiting demo session to prevent unauthorized page redirect.

## Problem

When users clicked "Salir" (Exit) from the demo session, they were redirected to the unauthorized page (`/unauthorized`) instead of the demo landing page (`/demo`).

## Root Cause

The `handleExpiration()` function in DemoBanner.tsx was clearing localStorage and navigating to `/demo`, but was NOT clearing the auth store. This created an inconsistent state:

- `isDemoMode = false` (localStorage cleared)
- `demoSessionId = null` (localStorage cleared)
- `isAuthenticated = true` (auth store NOT cleared - still has demo user)

The `useHasAccess()` hook checks:
```typescript
return isAuthenticated || (isDemoMode && !!demoSessionId);
```

After clearing localStorage but not auth:
- `isAuthenticated = true` but the demo session is invalid
- `isDemoMode = false` and `demoSessionId = null`
- Result: `useHasAccess()` returns `false`

When navigating to `/demo`, the ProtectedRoute checked access and found it was `false`, redirecting to `/unauthorized`.

## Solution

Call `logout()` on the auth store before navigating to clear the demo user session completely. This ensures:
- Auth store is cleared (`isAuthenticated = false`)
- User is properly logged out from demo session
- Navigation to `/demo` succeeds without authentication check

## Additional Improvements

- Also clear `virtual_tenant_id` and `subscription_tier` from localStorage
- Updated comment to clarify navigation intent

## Files Changed

- frontend/src/components/layout/DemoBanner/DemoBanner.tsx:73-74
  - Added auth store logout before navigation
  - Added clearing of virtual_tenant_id and subscription_tier
  - Updated comment for clarity

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/components/layout/DemoBanner/DemoBanner.tsx

@@ -62,18 +62,22 @@ export const DemoBanner: React.FC = () => {
     localStorage.removeItem('demo_account_type');
     localStorage.removeItem('demo_expires_at');
     localStorage.removeItem('demo_tenant_id');
+    localStorage.removeItem('virtual_tenant_id');
+    localStorage.removeItem('subscription_tier');
 
     // Clear API client demo session ID and tenant ID
     apiClient.setDemoSessionId(null);
     apiClient.setTenantId(null);
 
+    // Clear auth store to remove demo user session
+    const { useAuthStore } = await import('../../../stores/auth.store');
+    useAuthStore.getState().logout();
+
     // Clear tenant store to remove cached demo tenant data
     const { useTenantStore } = await import('../../../stores/tenant.store');
     useTenantStore.getState().clearTenants();
 
-    // Clear notification storage to ensure notifications don't persist across sessions
-    // Since useNotifications hook doesn't exist, we just continue without clearing
-
+    // Navigate to demo landing page
     navigate('/demo');
   };