dragons/ - one sub-folder per custom summonable dragon, holding that dragon's GeckoLib
geo model (.geo.json), its animation (.animation.json) and its texture (.png). The <folder
name> is the dragon id shown in /sdu wish -> New Dragon.

/sdu wish -> New Dragon generates a DMZ dragonball pack under <gamedir>/dragonballs/<id>/
whose asset definitions point at these files (and at the matching dragonballs/<name>/ set).
A fully custom dragon registers its entity, radar item and ball blocks on the next server
restart, then it can be summoned like shenron/porunga.
