feat(abilities): add passive feats system (Weapon Focus, Iron Will, Dodge, Point-Blank Shot)

src/pf1e_simulator/combat.py

@@ -357,11 +357,25 @@ class CombatEngine:
                 return _FLANK_BONUS
         return 0
 
-    def _stat_modifiers(self, state: CombatantState, target: str) -> list[StatModifier]:
-        """Collect all StatModifiers for ``target`` from effects + conditions."""
+    def _stat_modifiers(
+        self, state: CombatantState, target: str, *, weapon_name: str | None = None
+    ) -> list[StatModifier]:
+        """Collect all StatModifiers for ``target`` from effects, conditions, and features.
+
+        ``weapon_name`` filters out modifiers with a ``weapon_filter`` that
+        doesn't match (e.g. Weapon Focus (Pistol) only applies to "Pistol").
+        Modifiers without a ``weapon_filter`` are always included.
+        """
         mods = [e for e in state.effects if e.target == target]
         for cond in state.conditions:
             mods.extend(m for m in cond.modifiers if m.target == target)
+        for feat in state.combatant.features:
+            for m in feat.effects:
+                if m.target != target:
+                    continue
+                if m.weapon_filter is not None and m.weapon_filter != weapon_name:
+                    continue
+                mods.append(m)
         return mods
 
     def resolve_attack(
@@ -378,7 +392,7 @@ class CombatEngine:
         penalty = self.range_penalty(weapon, dist_ft)
         flank = self._flanking_bonus(attacker, target) if weapon.kind == "melee" else 0
         base_bonus = bonus_override if bonus_override is not None else weapon.attack_bonus
-        atk_mods = self._stat_modifiers(attacker, "attack")
+        atk_mods = self._stat_modifiers(attacker, "attack", weapon_name=weapon.name)
         attack_mod = resolve_modifiers(atk_mods)
         total = roll + base_bonus + penalty + flank + attack_mod
         ac = target.combatant.ac.total + resolve_modifiers(self._stat_modifiers(target, "ac"))
@@ -401,7 +415,7 @@ class CombatEngine:
                 confirm = self._rng.d20()
                 confirm_total = confirm + base_bonus + penalty + flank + attack_mod
                 crit = confirm != _NATURAL_ONE and confirm_total >= ac
-            dmg_mods = self._stat_modifiers(attacker, "damage")
+            dmg_mods = self._stat_modifiers(attacker, "damage", weapon_name=weapon.name)
             damage = sum(c.formula.roll(self._rng) for c in weapon.damage) + weapon.damage_bonus
             damage += resolve_modifiers(dmg_mods)
             if crit: