tanimtanzilislam/mern-CRM ? reverse-engineered prompt

Build me a small CRM web app where I can keep track of customers and leads. I want to be able to sign in, then add, edit, view, and delete customer records with name, email, phone, company, status, and notes. The status should cover lead, active, and inactive, and the app should feel simple and clean for everyday use.

Please make it a full working app with a React front end and a Node and Express backend connected to MongoDB. Set it up so the first registered user becomes an admin, then only admins can create more users. Include basic roles like admin, sales_manager, and staff, and make sure the API protects routes properly when someone is not signed in or does not have permission.

I want it to run locally with clear setup instructions, and if you need to check current docs or best practices, go ahead and look them up online.