[…]
If you like, add these three lines to the beginning of your .tex file to force TeXShop to use ConTeXt-CLD:
------------CUT HERE--------------
--[[
%!TEX TS-program = ConTeXt-CLD
]]--
------------CUT HERE--------------
You need all three lines. The TeX comment has to be enclosed in a Lua comment. The double hyphen after the "]]" is optional, I think, but I've seen it done that way. (As a neophyte, I imitate.)
Thanks for the information: indeed the three lines above allow a CLD code in a TEX file to be typeset by ConTeXt, using the TeXShop engine created with your indications.