For those following along outside of North America, it turns out that there’s nothing about the circuit that needs to change to switch 230VAC. The CUI power supply works on 90-240VAC 50/60 Hz, and the triac will work just as well at 230V as 120V.

With a higher voltage, you can increase the design power to 400W without changing anything about the circuit or board (except, of course, the outlet).