so-fancy/diff-so-fancy ? reverse-engineered prompt

Build me a small command line tool that makes git diffs look clean and easy to read instead of raw and noisy. I want it to work with normal git diff output, let me pipe unified diffs into it, and make the changed lines easier to scan with nicer colors, clearer file headers, and a better looking hunk layout. It should also work well as a git pager so I can use it for all my diffs and interactive patch views.

Please include a few simple options I can turn on or off, like stripping the plus and minus signs, changing the hunk header style, using Unicode or plain ASCII rulers, and showing short file headers. Make it behave nicely in a terminal, keep the output readable, and add basic docs so I know how to install it and set it up with git. If you need to, look up current docs online for any small compatibility details.