fix(rules): restrict nauseated creatures to a single move action

PF1e (SRD Conditions, nauseated): "The only action such a character can take is a single move actions per turn." _NAUSEA_MOVE_KINDS now holds only genuine move actions (move, stand_up, retrieve_weapon, repair_weapon): the 5-foot step and dropping prone are free actions and are dropped by the nauseated filter. The pinned filter test was retargeted; README updated.

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

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

tests/test_conformance_p1.py

@@ -409,11 +409,17 @@ def test_nauseated_cannot_cast_via_action_execution() -> None:
 
 
 def test_nauseated_filter_keeps_move_kinds_drops_everything_else() -> None:
-    for kind in ("move", "5foot_step", "stand_up", "drop_prone"):
+    # SRD nauseated: "The only action such a character can take is a single
+    # move action per turn" — only genuine move actions survive; the 5-foot
+    # step and dropping prone are free actions, not move actions.
+    for kind in ("move", "stand_up", "retrieve_weapon", "repair_weapon"):
         kept = _nauseated_filter((Action(kind=kind, target_id="foe"),))
         assert len(kept) == 1, kind
         assert kept[0].kind == kind, kind
-    for kind in ("attack", "cast_spell", "full_attack", "charge", "maneuver", "hex"):
+    for kind in (
+        "attack", "cast_spell", "full_attack", "charge", "maneuver", "hex",
+        "5foot_step", "drop_prone",
+    ):
         assert _nauseated_filter((Action(kind=kind, target_id="foe"),)) == (), kind