vaibhav-around/mern-understanding ? reverse-engineered prompt

Build me a small learning repo that shows three separate examples, one for basic todo app logic in JavaScript, one for async JavaScript and working with APIs, and one for a simple React todo interface.

I want each example to be easy to open and run on its own, with clear starter code, a basic folder setup, and enough comments so someone new to this can understand what is happening. The todo example should let a user add, finish, and remove items. The async example should show fetching data and handling loading and errors in a simple way. The React part should feel like a polished version of the todo app with a clean UI and the usual add, complete, and delete actions.

Keep the code simple and practical, since this is for understanding the basics. If you need anything current from docs, look it up online.