How do I do this? Installing the pen and adding some initial gcode to raise the Z axis above the bed so the nozzle doesn't touch isn't a problem, but what generates the drawing gcode?

I wrote code that generated this particular G-code for the Dragon curve.

In general, there's software to convert PostScript or DXF to G-code (used with e. g. engraving machines).

The G code to move in XY is simple enough (G0 x y) that you could write a converter yourself.

G code is simple, I'm just not sure how simple reading the curves would be. I worked around this by exporting as a png and having Cura slice that, then writing a script to extract a single layer. It works beautifully, now I want to see if I can make PCBs with it, it would be a revolution.