Refresh JWT before hard navigation on onboarding completion

After completing onboarding, the JWT cookie still has stale org data.
Fetching /api/auth/session triggers the JWT callback to query the DB
and write the updated cookie before the hard navigate to /.

Made-with: Cursor

src/app/(dashboard)/onboarding/page.tsx

@@ -126,6 +126,8 @@ export default function OnboardingPage() {
         }
 
         if (result.complete) {
+          // Refresh JWT cookie with updated org data before navigating
+          await fetch("/api/auth/session");
           window.location.href = "/";
           return result;
         }