feat: config-authoritative conf gates + cross-model IoU sack suppression

config.yaml

@@ -79,11 +79,11 @@ models:
   # perspective min_valid_area filter still applies on top).
   detection_params:
     truck:
-      conf: 0.35
+      conf: 0.45 # live gate was hardcoded 0.45; config authoritative now
       iou: 0.7
       min_bbox_area: 5000
     sack:
-      conf: 0.3 # default 0.35
+      conf: 0.4 # live gate used to hardcode 0.50; 0.40 compromise (config is authoritative)
       iou: 0.7
       min_bbox_area: 1500
     box:
@@ -107,6 +107,9 @@ counting:
   camera_noise_deadband: 50
   # Effective values below match zones.json (which previously overrode predict.py defaults).
   duplicate_circle_radius: 30
+  # Drop sack detections overlapping a box detection (cross-model IoU) — v4 has
+  # no box class, so white boxes get labeled "sack"; box model always wins.
+  cross_class_iou: 0.4
   min_valid_area: 15000
   max_reid_transit_distance: 400
   circle_stay_timeout_sec: 10.0