I had written a rather lengthy post describing this process in detail, but it's been lost: while I was typing a URL, a preview window popup up below and when I x-ed out of it the page change/refreshed and I lost everything. Argh...
So I'm now going to keep it short and sweet: a WP plugin for adding the Tipalink App to WP sites has been created and added to the official WordPress.org plugin repository: https://wordpress.org/plugins/tipalink/.
This is a milestone, because it will make adding the service to websites very very easy for users with WP sites (which is like, what, 80% of individuals and small businesses?!). All it does is add a script and meta tag to the head of a site. The script does the heavily lifting: generates the app in an embedded iframe and displays it as on overlay when opened.
Next project is browser extension for "advanced users". ;)