Zalman, my post was sent before yours appeared hours later.
But nevertheless, I will break it to you gently, depite all your sources, it is not at all clear that it is a halacha, rather than a hanhaga tova. They all say it is the derech of a woman not to go out much, etc., but not any clear issur. It is a matter of judgment.
Your quote that the SHulchan Oruch E”H 73 says Kol Kevudah is actually a quote from Hagahos R. Zalman. The mechaber doesn’t say it, nor does the Rama. The Rama says Isha lo sargil atzma laztzeis harbeh. She should not get into the habit of going out a lot (or excessively) she’ain yofi l’isha ella laishev bzavyos beisa. It is the beauty of a woman to stay in the confines of her home. This is a matter of beauty, not any clear cut prohibition. If it were, no women would be allowed to work, yet ruba dreuba of all chareidi kollel wives work a whole day.
Sorry, you did a lot of beautiful research, but did not succeed in any kind of a proof. (There is none, so don’t soend any more time looking.)