eyuleo/fo-exercises — reverse-engineered prompt

I want this repo turned into a clean, beginner friendly TypeScript exercises project, split into four parts that feel complete and easy to review. Each part should have a handful of simple exercises or examples with working code, sensible filenames, and short comments so I can understand what each one is meant to show. Make it easy to run from the repo without a lot of setup, and keep the style consistent across all four parts.

Please fill in anything missing with reasonable choices, but keep the scope modest and focused on practice rather than building a big app. Add a short README that explains what the project is, how to install and run it, and what each part covers in plain English. If tests make sense, include a few basic ones, but only if they help show the exercises are working.

If you need to, look up current TypeScript docs online, just keep everything simple and straightforward.