fix(rules): correct P1 PF1e conformance bugs (area saves, concentration, prone, slots, helpless, nauseated)

tests/test_prone_actions.py

@@ -7,8 +7,10 @@ removes the ``prone`` condition from BOTH representations — the duration-track
 ``conditions`` list (how ``drop_prone`` applies it). ``drop_prone`` is a free
 action that goes prone until the combatant stands up. Rejections: standing up
 while not prone → ``not_prone``; dropping while already prone →
-``already_prone``. The engine's existing prone behaviour (flat -4 AC in
-``_stat_modifiers``, -4 ranged attacks) is unchanged.
+``already_prone``. The engine's prone modifiers follow the CRB (B3
+conformance): a prone attacker takes -4 on melee attacks (ranged weapons are
+treated as crossbow-exempt — usable at -4, the model cannot tell them apart);
+a prone defender takes -4 AC vs melee and gains +4 AC vs ranged.
 """
 from __future__ import annotations