garrison_90 (bond_actived_maxstack, "当前已激活且层数最多的盟约层数+1(每场作战至多10层)"):
fireGain keeps the instance's count and passes the rest uncapped to gainLayers, so a
change of the highest bond no longer grants a fresh 10 / 20 (PR #178 review). Other
bond types keep the per-(instance, bond) cap. Local to garrisons/battle.js.
Golden: no scenario moved.