asim9115/golang ? reverse-engineered prompt

Build me a simple Go learning playground that shows off the basics in a clean, easy to browse way.

I want a small set of example programs and snippets that cover common things a beginner would want to try, like structs, methods, interfaces, slices, maps, pointers, functions, conversions, JSON, files, HTTP requests, parsing, time, goroutines, channels, defer, and a few simple web and API examples.

Keep it organized so each topic lives in its own place and I can open one example at a time without getting lost. If it makes sense, include a couple of small demo apps too, like a basic CRUD example, a Mongo example, and a simple server or streaming example. Make it easy to run and read, with clear names and short comments. If you need to check current docs online for anything, go ahead.