I am very sorry about the loss of your colony and those temperatures are monumental.
For future consideration, have you thought about white fabric shade awnings that could be temporarily put up during periods of high heat? Air passes through them, they bring shade and reflect sun/heat.
It’s something we don’t deal with in the northeastern U.S. but is definitely something we need to be thinking about.
I’m curious also about the bees remaining inside and expiring when generally they would congregate (during periods of high heat) beneath the hive all bearded up… are the hive bodies elevated well off the ground?
Thank you for sharing your tragedy so we call all be better prepared and have an emergency action plan for weather extremes.