Update difficulty table metadata paths (test)

test/difficulty_table.json

@@ -1,6 +1,6 @@
 {
   "meta": {
-    "parent_difficulty_table": "/home/jiarong/VisPhyWorld/data/difficulty_table__dataset_sub__en_with_3d.json",
+    "parent_difficulty_table": "/home/jiarong/VisPhyWorld/data/difficulty_table__dataset_sub.json",
     "dataset_dir": "/home/jiarong/VisPhyWorld/data/dataset_test",
     "language": "en",
     "counts": {
@@ -11,7 +11,8 @@
     "total": 49,
     "labeled": 49,
     "remaining": 0,
-    "exported_at": "2026-02-06T01:01:10.239124-05:00"
+    "exported_at": "2026-02-08T17:19:05.648370-05:00",
+    "detection_dir": "/home/jiarong/VisPhyWorld/data/detection_json_test"
   },
   "selections_by_video": {
     "task00000_000": "easy",