Correct the pose composition for a non-180° rest (rest-relative swing axis), backward-compatible with the 13-core fallback

src/game/npc_avatar.gd

@@ -535,10 +535,14 @@ func _pose_bone(bone_name: String, angle: float, axis: Vector3) -> void:
 	if not _bone_indices.has(bone_name):
 		return
 	var index: int = _bone_indices[bone_name]
-	# Bone pose rotation is the absolute local orientation, not an offset from
+	# The pose is rest-relative (global = parent * rest * pose), so the proxy's
-	# rest; compose with the rest rotation so identity preserves the bind pose.
+	# world-space swing axis must be expressed in the bone's rest-local frame.
+	# `rest * Quaternion(rest.inverse() * axis, angle)` swings around the world
+	# `axis`; for the old rig (rest = 180 deg) this reduces to the legacy
+	# `rest * Quaternion(axis, angle)`, so the 13-core fallback is unchanged.
 	var rest := _skeleton.get_bone_rest(index).basis.get_rotation_quaternion()
-	_skeleton.set_bone_pose_rotation(index, rest * Quaternion(axis, angle))
+	var local_axis := rest.inverse() * axis
+	_skeleton.set_bone_pose_rotation(index, rest * Quaternion(local_axis, angle))
 
 func _build_body(npc_type: int) -> void:
 	_rig = Node3D.new()