Petra will assign guards to wonders that it builds in the wonder victory condition. This is handled largely in the same way as heroes in regicide. Around ten units will be selected to guard, and the number is based on the defensive personality trait. Initially I planned to add guards to the wonder's foundation as well, but currently foundations can't be guarded.
This diff moves the for (let evt of events.Destroy) loop above the early return in gameTypeManager, as these events now need to be checked in wonder games, as well as regicide.
Eventually, it would be nice for Champion units to be preferentially selected as guards, possibly switching with any citizen soldiers that are already guarding.