Add dockerized detector and UI cleanup

tests/test_vision.py

@@ -1,6 +1,6 @@
 import numpy as np
 
-from app.vision import BBox, crop_image, detect_salient_object, square_bbox
+from app.vision import BBox, crop_image, detect_salient_object, select_primary_bbox, square_bbox
 
 
 def test_square_bbox_is_square_and_inside_bounds():
@@ -28,3 +28,10 @@ def test_detect_salient_object_finds_rectangle():
     assert bbox is not None
     assert bbox.w >= 45
     assert bbox.h >= 45
+
+
+def test_select_primary_bbox_falls_back_when_detector_disabled():
+    image = np.zeros((100, 120, 3), dtype=np.uint8)
+    bbox, method = select_primary_bbox(image, detector="center")
+    assert method == "center_fallback"
+    assert bbox.w == bbox.h