fix(rules): cure spells damage undead instead of healing

SRD Cure Light Wounds: 'Since undead are powered by negative energy,
this spell deals damage to them instead of curing their wounds. An
undead creature can apply spell resistance, and can attempt a Will save
to take half damage.'

- _apply_heal_effect takes the rolled save; an undead target takes the
  rolled healing as damage (halved on a successful save; SR already
  resolved upstream, DR never applies to spell energy, no bleeding stop
  or stabilization). Living targets are bit-identical.
- cure_light/cure_moderate descriptions fixed: the SRD save line is
  'Will half (harmless)', not 'negates'.
- Deafened 20% verbal spell failure DEFERRED to the README « Limites
  hors perimetre »: SpellSpec carries no components data (would need a
  verbal flag on all 108 spells) and sound-based Perception is not
  modeled either.

README.md

@@ -1583,6 +1583,17 @@ plutôt que bricolées) :
   en revanche deux créatures de même taille (Small et plus) ne partagent
   jamais une case, et la co-occupation de plusieurs Tiny sur une même case
   n'est pas modélisée.
+- **Échec d'incantation pour un personnage sourd hors périmètre** (SRD
+  « Conditions — Deafened » : « a 20% chance of spell failure when casting
+  spells with verbal components ») : le moteur ne porte pas la composante
+  verbale des sorts (`SpellSpec` n'a pas de champ `components` — il
+  faudrait l'encoder sur les 108 sorts du registre) et ne modélise pas non
+  plus le jet de Perception DD 20 basé sur le son ni l'échec automatique
+  associé ; la condition `deafened` reste donc un porteur de modificateurs
+  (−4 d'initiative) sans la faillibilité d'incantation. Le soin des
+  morts-vivants par les sorts de soin (`cure`) est en revanche modélisé :
+  SRD « Cure Light Wounds » — « this spell deals damage to them instead of
+  curing their wounds [...] can attempt a Will save to take half damage ».
 
 Limites de sorts (conformance D6-D9, documentées plutôt que bricolées) :
 

data/spells/cure_light_wounds.json

@@ -13,5 +13,5 @@
       "scaling_flat": { "amount": 1, "per_levels": 1, "max": 5 }
     }
   ],
-  "description": "Cures 1d8 points of damage +1 point per caster level (maximum +5). Will save negates (harmless)."
+  "description": "Cures 1d8 points of damage +1 point per caster level (maximum +5). Will half (harmless); since undead are powered by negative energy, the spell deals damage to them instead (Will half, SRD cure light wounds)."
 }

data/spells/cure_moderate_wounds.json

@@ -13,5 +13,5 @@
       "scaling_flat": { "amount": 1, "per_levels": 1, "max": 10 }
     }
   ],
-  "description": "Cures 2d8 points of damage +1 point per caster level (maximum +10). Will save negates (harmless)."
+  "description": "Cures 2d8 points of damage +1 point per caster level (maximum +10). Will half (harmless); since undead are powered by negative energy, the spell deals damage to them instead (Will half, SRD cure moderate wounds)."
 }

src/pf1e_simulator/combat.py

@@ -6287,7 +6287,7 @@ class CombatEngine:
         if isinstance(effect, HealEffect):
             return self._apply_heal_effect(
                 effect, target, caster_level=caster.combatant.level,
-                empower=empower, maximize=maximize,
+                empower=empower, maximize=maximize, saved=saved,
             )
         return self._apply_buff_effect(effect, target, spell_name=spell_name)
 
@@ -6475,6 +6475,7 @@ class CombatEngine:
         caster_level: int,
         empower: bool,
         maximize: bool,
+        saved: bool,
     ) -> str:
         formula = effect.effective_formula(caster_level)
         heal = formula.roll(self._rng)
@@ -6482,6 +6483,17 @@ class CombatEngine:
             heal = formula.max_value()
         if empower:
             heal = int(heal * 1.5)
+        if target.combatant.creature_type == "undead":
+            # PF1e (SRD "Cure Light Wounds"): "Since undead are powered by
+            # negative energy, this spell deals damage to them instead of
+            # curing their wounds. An undead creature can apply spell
+            # resistance, and can attempt a Will save to take half damage."
+            # SR is resolved upstream (_spell_delivery_blocked); the rolled
+            # save halves here. Cure damage is spell energy: never reduced by
+            # DR, and it does not stop bleeding or stabilize.
+            dmg = heal // 2 if saved else heal
+            target.hp -= dmg
+            return f"{dmg} damage (undead)"
         old_hp = target.hp
         target.hp = min(target.hp + heal, target.combatant.hp_max)
         # PF1e (CRB, Stable Characters and Recovery): "If any sort of healing

tests/test_bleeding_confused.py

@@ -103,7 +103,7 @@ def test_heal_spell_clears_bleed() -> None:
     a.conditions.append(BLEEDING)
     result = eng._apply_heal_effect(
         HealEffect(formula=parse_dice("1d8")), a, caster_level=1,
-        empower=False, maximize=False,
+        empower=False, maximize=False, saved=False,
     )
     assert result == "+5 HP"
     assert a.hp == 55

tests/test_cure_undead.py

@@ -0,0 +1,80 @@
+"""Cure spells damage undead instead of healing (Task 11 conformance).
+
+SRD "Cure Light Wounds" (spells/cure-light-wounds.md): "Since undead are
+powered by negative energy, this spell deals damage to them instead of curing
+their wounds. An undead creature can apply spell resistance, and can attempt
+a Will save to take half damage." The engine resolves SR upstream and the
+rolled Will save halves the damage here; living targets keep healing exactly
+as before.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from tests.test_spells import _make_caster, _make_engine, _make_target
+
+if TYPE_CHECKING:
+    from pf1e_simulator.models import Combatant
+
+
+def _undead(cid: str = "skeleton", *, hp_max: int = 20) -> Combatant:
+    return _make_target(cid=cid, hp_max=hp_max).model_copy(
+        update={"creature_type": "undead"}
+    )
+
+
+def _caster() -> Combatant:
+    return _make_caster().model_copy(update={"spells": ["Cure Light Wounds"]})
+
+
+class TestCureDamagesUndead:
+    """Given: a level-5 caster (Cure Light Wounds = 1d8+5) and an undead target
+
+    When: the cure spell is delivered
+    Then: the undead takes damage instead of healing.
+    """
+
+    def test_failed_save_deals_full_damage(self) -> None:
+        """Given: an undead at 20 hp
+        When: cured and it fails the Will save (d20=1), the die rolls 8
+        Then: it takes the full 13 damage (8+5) instead of healing."""
+        engine, c, t = _make_engine(
+            _caster(), _undead(), [1, 8], target_pos=(1, 0), target_side="players"
+        )
+        engine._cast_spell(c, t, "Cure Light Wounds")
+        assert t.hp == 7
+        assert any("13 damage (undead)" in line for line in engine._transcript)
+
+    def test_successful_save_halves_the_damage(self) -> None:
+        """Given: an undead at 20 hp
+        When: cured and it succeeds the Will save (natural 20), the die rolls 8
+        Then: it takes half damage (13 // 2 = 6)."""
+        engine, c, t = _make_engine(
+            _caster(), _undead(), [20, 8], target_pos=(1, 0), target_side="players"
+        )
+        engine._cast_spell(c, t, "Cure Light Wounds")
+        assert t.hp == 14
+        assert any("6 damage (undead)" in line for line in engine._transcript)
+
+    def test_undead_destroyed_by_cure_damage(self) -> None:
+        """Given: an undead at 10 hp
+        When: a failed-save cure deals 13 damage
+        Then: the undead is destroyed (undead die at hp <= 0)."""
+        engine, c, t = _make_engine(
+            _caster(), _undead(hp_max=10), [1, 8], target_pos=(1, 0), target_side="players"
+        )
+        engine._cast_spell(c, t, "Cure Light Wounds")
+        assert t.dead is True
+
+    def test_living_target_still_heals(self) -> None:
+        """Given: a living ally at 5/20 hp
+        When: cured with a die roll of 8
+        Then: it heals 13 hp (behavior unchanged for the living)."""
+        engine, c, t = _make_engine(
+            _caster(), _make_target(), [1, 8], target_pos=(1, 0), target_side="players"
+        )
+        t.hp = 5
+        engine._cast_spell(c, t, "Cure Light Wounds")
+        assert t.hp == 18
+        assert any("+13 HP" in line for line in engine._transcript)

tests/test_dying_and_crits.py

@@ -221,7 +221,7 @@ def test_heal_spell_stabilizes_dying_creature() -> None:
     eng._rng = ScriptedRng([1])  # 1d8 -> 1: only 1 point cured
     result = eng._apply_heal_effect(
         HealEffect(formula=parse_dice("1d8")), s, caster_level=1,
-        empower=False, maximize=False,
+        empower=False, maximize=False, saved=False,
     )
     assert result == "+1 HP"
     assert s.hp == -2
@@ -253,7 +253,7 @@ def test_heal_to_positive_hp_does_not_stabilize() -> None:
     eng._rng = ScriptedRng([8])
     eng._apply_heal_effect(
         HealEffect(formula=parse_dice("1d8")), s, caster_level=1,
-        empower=False, maximize=False,
+        empower=False, maximize=False, saved=False,
     )
     assert s.hp == 5
     assert s.stabilized_hp is None