Per @ha0ye , "I don't know how useful it would be for an end-user to be able to go through model projections in the Shiny app and then output a reproducible R Markdown report, but that could be a consideration as a feature. (not necessary here, but perhaps if stakeholder feedback shows it as a useful inclusion)"
If end users express a desire for this feature, I will pursue it. In the meantime, saving here as a feature request.