Wired http server?

Well, the obvious wired solution is to use Ethernet - the WIZnet module does that really well and is by far the most reliable way to get network connectivity as well.

If you're running Linux you could do something nasty with netcat (nc), like nc -l -p 1234, and then pipe that to and from Espruino's USB serial port, but then you still have to bodge up an interface between USB and Espruino's socket layer (using JSNetwork, a bit like is done in the ESP8266 code).

Come to think of it, you might be able to get Linux to appear as a kind of ESP8266 device (using AT commands to access the net) - something might exist, or it wouldn't be too hard to write your own ESP8266 faker, there are only a handful of commands it needs to understand. Then you just use the ESP8266 library itself.