lint: ruff-clean testbed (blocking file write to thread, unused vars)

testbed/tests/test_world.py

@@ -4,7 +4,7 @@ import math
 
 import pytest
 
-from testbed.room.world import ROOM_SIZE, Beacon, Box, Room
+from testbed.room.world import ROOM_SIZE, Room
 
 
 def test_spawn_state():
@@ -79,7 +79,7 @@ def test_turn_clamps_pitch():
 
 def test_look_at_beacon():
     room = Room()
-    yaw, pitch = room.look_at_beacon()
+    yaw, _pitch = room.look_at_beacon()
     dx = room.beacon.x - room.capsule.x
     dz = room.beacon.z - room.capsule.z
     assert yaw == pytest.approx(math.degrees(math.atan2(dx, dz)))