eclipse-mosquitto/mosquitto — reverse-engineered prompt

I want this turned into a working MQTT broker project I can build and run from source without a lot of manual setup. Please make sure the broker starts easily for local testing, and also supports a proper config for devices connecting from other computers. Include the usual command line tools so I can publish messages, subscribe to topics, do request reply tests, and handle basic admin tasks like creating password files and controlling the broker.

Please keep it practical and friendly for someone who just wants to try it first, then lock it down. I want a simple local demo where one terminal subscribes and another publishes a hello world message, plus a safer example config with a listener and username and password authentication instead of anonymous public access. If there are optional features like TLS, HTTP API, or persistence, wire them in when reasonable but do not overcomplicate the default setup.

Add clear build and run instructions for the main platforms. Look up current docs online if you need to.