feat(mod-api): expose charge decision hook

src/battle/BattleState.lua

@@ -3980,7 +3980,17 @@ function BattleState:performMove(user, target, moveInst, isCalled)
   -- record (chargeText) and the invulnerability from semiInvulnerable,
   -- falling back to the id tables (Fly AND Dig go semi-invulnerable:
   -- ChargeEffect sets INVULNERABLE for both)
-  if record and record.charge and not releasing then
+  local chargeRequired = record and record.charge ~= nil and not releasing
+  if chargeRequired and Runtime.wantsHook("battle.charge_required") then
+    local required = Runtime.call("battle.charge_required", function(c)
+      return c.charge
+    end, {
+      battle = self, user = user, target = target, move = move,
+      charge = true, isCalled = isCalled or false,
+    })
+    chargeRequired = required ~= false
+  end
+  if chargeRequired then
     self:cancelMoveAnim()
     user.charging = moveInst
     user.chargeReady = true

src/battle/gen2/Battle.lua

@@ -1494,6 +1494,15 @@ function Battle:useMove(attacker, defender, moveId)
   if def.effect == "EFFECT_SOLARBEAM" and self.weather == "sun" then
     charge = nil
   end
+  if charge and not charging and Runtime.wantsHook("battle.charge_required") then
+    local required = Runtime.call("battle.charge_required", function(c)
+      return c.charge
+    end, {
+      battle = self, user = attacker, target = defender, move = def,
+      charge = true, isCalled = (self.copyDepth or 0) > 0,
+    })
+    if required == false then charge = nil end
+  end
   if charge and not charging then
     state.chargeMove = moveId
     state.vanished = charge.vanish or nil