Fix JWT authentication persistence issue in a React application

I have a React application where users are able to log in successfully, but they are not staying logged in after refresh or navigation. I need a developer to identify and fix the JWT authentication persistence issue. Scope of work: * Identify why the JWT token/session is not persisting correctly in the React application * Check authentication flow (token storage, cookies, headers, or localStorage implementation) * Apply a clean fix to ensure user remains logged in across refresh and routes * Confirm login works end-to-end after fix Requirements: * Strong experience with React and JWT authentication * Good understanding of cookies, localStorage, and frontend authentication flows * Ability to quickly debug authentication issues * Deliver within 24 hours