References that contain a single URL should generate a 'Convert' button in the initial context popup, allowing you to feed the URL into Citoid.

Ah, I see. But sometimes the link is generated from some template like <ref>{{Example|page.html}}</ref> > <ref>http://www.example.org/page.html</ref>. The steps for this case should then be: get the url from the url parameter, insert it to the reference body as bare and click Insert. Click Convert in the Inserted citation. This is not really straightforward.

The steps for this case should then be: get the url from the url parameter

This is going to be basically impossible without coming up with a whole new extension to TemplateData to define which parameters are URL parameters. The example you give does not appear to be that common, at least on the wikis I've looked at, so it would probably be hard for us to justify the effort.

On enwiki they use thousands of templates like this. On cswiki we change them to our standard citation templates (when someone translates the article from enwiki with those templates left), but it can be only done by manually rewriting because of this blocker. Solving this would make the problem much easier.

This task is about there is no Citoid icon in the mini editor, so it is could be a dupe of T179773?