Support Multiprocessing on Windows/Mac

[GrandpaEJ]

Problem

The current native multiprocessing implementation relies on , which is only available on Linux/Unix systems.
Windows and macOS currently fall back to the standard threading model (1 process, multiple threads) due to the GIL, limiting performance to ~25k RPS.

Proposed Solution

Explore 'Socket Passing' or 'Socket Sharing' techniques to allow multiple worker processes on Windows/Mac.

• Parent process binds the socket.
• Pass the file descriptor to child processes.
• Child processes rebuild the socket from the FD.

This would allow 100k+ RPS performance on all platforms.