fix(spells): make the bleed spell bleed

PF1e (SRD spells/bleed.md): "Saving Throw Will negates" and the target takes 1 point of damage per round. Two divergences: the JSON declared a Fortitude save, and the bleeding condition never set the engine's bleed_damage field, so the spell was a no-op. Bleed now saves Will; _apply_condition_effect sets bleed_damage = 1 when a spell applies bleeding, and _decrement_durations lands the final tick as the last bleeding condition expires before clearing the field (heal-path clearing already existed in _stop_bleeding). README updated.

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

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

tests/test_spell_registry_batch1.py

@@ -42,7 +42,7 @@ _BATCH1: dict[str, tuple[str, int, str, str, str]] = {
     "Bane": ("bane", 1, "enchantment", "medium", "will"),
     "Bear's Endurance": ("bears_endurance", 2, "transmutation", "touch", "fort"),
     "Bladed Dash": ("bladed_dash", 1, "transmutation", "close", "none"),
-    "Bleed": ("bleed", 0, "necromancy", "close", "fort"),
+    "Bleed": ("bleed", 0, "necromancy", "close", "will"),
     "Bless": ("bless", 1, "enchantment", "medium", "none"),
     "Blindness/Deafness": ("blindness_deafness", 2, "necromancy", "medium", "will"),
     "Charm Person": ("charm_person", 1, "enchantment", "medium", "will"),