fix(rules): tick bleed and auto-fail stabilization for a dying creature

PF1e (CRB, Stable Characters and Recovery): characters taking continuous damage such as bleed automatically fail all Constitution checks made to stabilize, losing 1 hp per round in addition to the continuous damage. _process_dying never applied bleed (only _turn_gate, reached by active creatures did), so a bleeding dying creature lost 0 hp per round. It now ticks bleed_damage at the start of the dying turn and auto-fails the check (no d20 consumed), then evaluates death.

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

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

src/pf1e_simulator/combat.py

@@ -1816,7 +1816,9 @@ class CombatEngine:
         (d20 + Con modifier - negative hp total); a natural 20 auto-succeeds.
         Failure bleeds 1 more hp; success stabilizes (no further loss while
         stable). New damage below the stabilizing hp resumes dying; healing to
-        hp >= 0 resets stabilization for any future downing.
+        hp >= 0 resets stabilization for any future downing. A creature taking
+        continuous damage (bleed) instead ticks the bleed and AUTOMATICALLY
+        FAILS the check (CRB, Stable Characters and Recovery).
         """
         if state.dead:
             return
@@ -1827,6 +1829,23 @@ class CombatEngine:
             if state.hp >= state.stabilized_hp:
                 return
             state.stabilized_hp = None
+        # PF1e (CRB, Stable Characters and Recovery): "Characters taking
+        # continuous damage, such as from an acid arrow or a bleed effect,
+        # automatically fail all Constitution checks made to stabilize. Such
+        # characters lose 1 hit point per round in addition to the continuous
+        # damage." This is the inactive creature's once-per-round slot (the
+        # active path already ticked bleed in _turn_gate), so the bleed damage
+        # is applied here and the d20 check is skipped (auto-fail).
+        if state.bleed_damage > 0:
+            self._apply_bleed_damage(state)
+            hp_before = state.hp
+            state.hp -= 1
+            self._log(
+                f"round {self._current_round} {state.combatant.id}: dying — continuous "
+                f"damage auto-fails the Constitution check, loses 1 hp "
+                f"(hp {hp_before} -> {state.hp})"
+            )
+            return
         con_mod = (state.combatant.abilities.con_score - 10) // 2
         penalty = -state.hp
         roll = self._rng.d20()