Summoned pets (not necro pets) now carry MASK_PET, so pet-targeted
AOE powers can find them. The checkForAggro pet scan is held off with
PET_AGGRO_ENABLED until it checks rune enemy lists, filters targets
and keeps pet targets (plan-mask-pet.md steps 2-4).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>