locustio/locust ? reverse-engineered prompt

Build me a load testing tool for my websites and APIs. I want to write the test scenarios in plain Python code. The idea is that I can define a user's behavior with simple tasks, like logging in or viewing a page, just by writing Python functions inside a class.

It needs to be scalable so I can run a distributed test across multiple machines to simulate thousands or even hundreds of thousands of concurrent users. It should also have a nice web-based dashboard where I can start the test, control the number of users, and watch the results in real-time with charts for things like response times and errors.

Basically, I'm looking for a developer-friendly performance testing framework that I can control with code but still get a great visual UI to see what's happening live.