fix: Add service to useEffect dependency array

Resolves react-hooks/exhaustive-deps warning in useAuthentication.
The service is a stable singleton so this has no behavioral change.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Gido Manders

src/hooks.tsx

@@ -29,7 +29,7 @@ export function useAuthentication<User>(): AuthenticationState<User> {
     return () => {
       service.unsubscribe(subscriber);
     };
-  }, []);
+  }, [service]);
 
   return state;
 }