I stumbled upon this thread while trying to figure out how to enable Arabic in Sublime …
So back in the days I was part of the team who ported a Bidi engine to ICU (both ICU4C & ICU4J), mainly the Arabic shaping engine responsible for the shaping of the Arabic characters into Arabic words and strings, you can even find my name in the ICU open source files until now: https://github.com/unicode-org/icu/blob/main/icu4c/source/common/ushape.cpp
So my proposal if someone from Sublime is interested is that I can help in adding the Arabic support to Sublime free of charge, I might be a bit rusty but as long as we don’t have a due date I believe I can handle it during my free time
Just let me know if you are interested
Regards