Getting Emacs proced.el to Show CPU and Memory on macOS

I have used the proced.el package in Emacs on Linux for years. It is
my go-to "ps as a buffer". A nicely formatted, colorized listing of
every running process, with auto-update and tree view. I use it far
more often than top, htop, or similar tools.

But on macOS I noticed something important is missing: no CPU or
memory columns.

The reason lives in Emacs itse...