Enhancement: Support for Proxy Protocol

[baltazartroisville]

Hi there,

First, thank you so much for your hard work on taxy! The project is impressively minimal and the built-in WebUI makes it incredibly user-friendly.

I wanted to suggest adding support for the Proxy Protocol v1 and/or v2 (invented by HAProxy), which would be very helpful for preserving client IP information when taxy is behind another proxy or load balancer or is used as a raw TCP proxy.

This would make taxy even more versatile in various deployment scenarios and prevent the reliance on HTTP proxying for having HTTP headers.

Helpful resources and informations:

• Proxy Protocol specification (HAProxy)
• HAProxy: Understanding PROXY Protocol
• Actively developed Rust crate with proxy protocol implementation

Thanks again for maintaining and developing this awesome tool!

Best regards! ❤️