feat: gate route_tuple helper

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

gates/gate.py

@@ -0,0 +1,15 @@
+# gates/gate.py
+import io
+import math
+
+import numpy as np
+import torch
+from PIL import Image
+
+from . import gate_bus
+
+MAX_ROUTES = 10
+
+
+def route_tuple(chosen, image, blocker, max_routes=MAX_ROUTES):
+    return tuple(image if i == chosen else blocker for i in range(max_routes))

tests/test_gate.py

@@ -0,0 +1,11 @@
+# tests/test_gate.py
+from gates import gate
+
+def test_route_tuple_places_image_at_chosen():
+    B = object()
+    t = gate.route_tuple(2, "IMG", B, max_routes=5)
+    assert t == (B, B, "IMG", B, B)
+
+def test_route_tuple_length_is_max():
+    B = object()
+    assert len(gate.route_tuple(0, "IMG", B, max_routes=10)) == 10