Seems like your local environment might be a bit broken then. Which as a non-R person, is a bit out of my league. @jcblum any suggestions on places to look for help?
Josh, thanks so much for your patience with this problem!
Well, after much sturm and drang, the application is now working at shinyapps.io.
Eventually I concluded that I would have to use packrat. Well that was no fun,
since it removed lots of packages it thought I didn't ever need anymore, including rsconnect! and forced the package git2r on me even though I don't use it, which of course proceeded to fail to build, and then my package (2 actually) had to be built again from install_github() and ...yada-yada.
But... now it is really working, the whole enchilada!
That solves a really critical problem for me.