fix(rules): scale Power Attack for two-handed weapons and apply its CMB penalty

src/pf1e_simulator/combat.py

@@ -2260,7 +2260,14 @@ class CombatEngine:
             sum(c.formula.roll(self._rng) for c in weapon.damage) + weapon.damage_bonus
         )
         damage += resolve_modifiers(dmg_mods)
-        damage += pa_amt * 2 if weapon.kind == "melee" else 0
+        # PF1e (CRB Power Attack): +2X damage with a melee weapon, +3X (the
+        # bonus increased by half) with a two-handed weapon, a one-handed
+        # weapon used in two hands, or a primary natural with 1.5x Strength
+        # (modeled via the weapon's `two_handed` flag). The off-hand /
+        # secondary-natural halving (-50%, +1X) is NOT modeled: two-weapon
+        # fighting is not in the engine (documented simplification).
+        if weapon.kind == "melee":
+            damage += pa_amt * (3 if weapon.two_handed else 2)
         if crit:
             damage *= weapon.crit_mult
         damage += sneak_total
@@ -3607,7 +3614,13 @@ class CombatEngine:
             if not state.active:
                 return
 
-        attacker_cmb = self._maneuver_cmb(state)
+        # PF1e (CRB Power Attack): the -X penalty applies to all melee attack
+        # rolls AND combat maneuver checks while the feat is active. The
+        # escape option that substitutes an Acrobatics/Escape Artist skill
+        # check is not penalized (a skill check is not a CMB check) — see
+        # _maneuver_escape.
+        pa_amt = self._power_attack_amt(state)
+        attacker_cmb = self._maneuver_cmb(state) - pa_amt
         target_cmd = self._maneuver_cmd(target)
         roll = self._rng.d20()
         total = roll + attacker_cmb

src/pf1e_simulator/models.py

@@ -239,7 +239,10 @@ class AttackSpec(_FrozenModel):
     the same entry twice. `reach_ft` applies to melee/touch kinds,
     `range_increment_ft` to ranged/touch kinds. `firearm` marks a ranged-touch
     weapon (gun) whose shots resolve against touch AC within the first range
-    increment and against full AC beyond it.
+    increment and against full AC beyond it. `two_handed` marks a weapon swung
+    in two hands (two-handed weapon, one-handed weapon used two hands, or a
+    primary natural with 1.5x Strength) — PF1e Power Attack rolls +50% damage
+    with such a weapon (CRB "Power Attack").
     """
 
     id: str
@@ -254,6 +257,7 @@ class AttackSpec(_FrozenModel):
     range_increment_ft: int | None = None
     count: int = Field(default=1, ge=1)
     firearm: bool = False
+    two_handed: bool = False
 
 
 class DamageReduction(_FrozenModel):