fix(spells): correct the sound burst save

PF1e (SRD spells/sound-burst.md): "Every creature in the area takes 1d8 points of sonic damage and must succeed on a Fortitude save to avoid being stunned for 1 round" — the Fortitude partial negates the stun only, never the dice. The damage component declared half_on_save: true, halving the sonic damage on a successful save. DamageEffect gains a save_negates flag (default True, existing behavior unchanged); sound_burst.json declares half_on_save: false + save_negates: false so the 1d8 is full regardless while the condition keeps save_negates. README updated.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/pf1e_simulator/spells.py

@@ -39,6 +39,11 @@ class DamageEffect:
     types: tuple[str, ...]
     # False = save negates (targeted); True = half damage on save (ray/line/cone/AoE)
     half_on_save: bool = False
+    # Only consulted when half_on_save is False. True = a successful save deals
+    # no damage (save negates, the targeted-spell default); False = the save has
+    # no effect on this damage at all (SRD Sound Burst: "Fortitude partial"
+    # negates only the stun — every creature takes the full dice regardless).
+    save_negates: bool = True
 
 
 @dataclass(frozen=True)
@@ -258,6 +263,7 @@ def _parse_effect(data: Json) -> SpellEffect:
             formula=parse_dice(_as_str(effect["formula"])),
             types=tuple(_as_str(t) for t in _as_list(effect["types"])),
             half_on_save=bool(effect.get("half_on_save", False)),
+            save_negates=bool(effect.get("save_negates", True)),
         )
     if effect_type == "condition":
         return ConditionEffect(