saurabhsoni08/mern-thinkboard ? reverse-engineered prompt

Build me a full stack notes app called NotesLab where people can sign up, log in, and manage their own private notes. I want users to be able to create, edit, delete, search, and view notes, with notes sorted by newest first. The app should keep each user’s notes separate so no one can see or change another person’s notes, and it should use secure login with JWT, HttpOnly cookies, password hashing, logout, and protected routes.

Also add a guest mode so someone can try the app without an account, and their guest notes should save in the browser so they stay after refresh. Make it feel polished and modern with a clean React frontend and a simple responsive UI.

On the backend, add rate limiting and solid security checks. Please include automated end to end tests too, especially for guest note CRUD, login and ownership protection, and cross user access. Use current docs online if you need to fill in any missing details.