Is there an iOS equivalent of Fluid for Mac?

I'd like to run a Freeboard.io dashboard (HTML+JavaScript) on an older iPad to visualize a bunch of things persistently. This would be fine as a Safari home-screen-ified app, except there's no way to prevent display sleep without globally changing the iPad's lock settings.

It's easy enough to programmatically disable sleep in an iOS app, but I don't want to pay $99/year for an Apple developer account just so I can make a UIWebView in an app that disables the sleep timer.

And yes, Panic's Status Board exists—but apparently it's buggy and not being actively developed anymore. It's more sensible than a $99/year subscription, but still not ideal.

What I'd love is the equivalent of Fluid.app for Mac, just for iOS and obviously with the option to disable the sleep timer.

Does a suitable iOS app exist, or would Apple reject any candidate because it'd be nothing more than a UIWebView wrapper?