Adithya5434/multiproxy-go — reverse-engineered prompt

Build me a small Go proxy server that can handle several kinds of proxy traffic on one single port. I want it to automatically detect what the client is trying to use and then route it correctly, so it should support normal HTTP proxying, HTTP CONNECT, a basic web proxy mode, SOCKS4 and SOCKS4a, SOCKS5 with optional username and password, and Minecraft TCP proxying too.

Please make it easy to run. On first start, if there is no config yet, it should create a default JSON config file, print a helpful message, and then let me edit it and restart. The config should cover the listen address and port and any auth settings that apply. Once running, it should relay traffic cleanly between client and target.

I also want a simple way to test it, like a small example script or commands that show SOCKS5 and HTTP usage. Keep the app straightforward and practical, and look up current Go docs online if you need to.