Detect the need for or use of the Worker & K/V updates

[BigBlueHat]

Free accounts only support 3 Page Rules, so we "fallback" to the redir Worker. Right now, most of that experience is manual...especially for later (post-creation) updates. Commands like show are frightening because they don't look at the Worker K/V or even state that the Worker is installed.

Additionally, with Worker's new "Custom Domain" feature, that could/should be used which would help provide a simpler mapping between those worlds (hopefully).