I don’t think that’s possible at the moment for reasons @d-hermit has already identified.
I will note that there is a functioning heatmap userscript:
This only works if you use a single browser (and progress would disappear if you cleared your browser data), though, as it stores the review information locally. You wouldn’t be able to see this information on an app, and any reviews done on the app wouldn’t count as progress on the heatmap.