🐛(frontend) prevent silent login during active calls

React Query refetches stale data on window focus, which triggers
silent login attempts for logged-out users.

If user data becomes stale (after 1 hour), silent login redirects
the user to the auth domain, potentially disconnecting them during calls.

To prevent this, user data is now considered non-stale
during active sessions.

If the user logs in via another tab, a manual page
reload will be required to refresh their session.

src/frontend/src/features/auth/api/useUser.tsx

@@ -15,7 +15,7 @@ export const useUser = () => {
   const query = useQuery({
     queryKey: [keys.user],
     queryFn: fetchUser,
-    staleTime: 1000 * 60 * 60, // 1 hour
+    staleTime: Infinity,
   })
 
   useEffect(() => {