fix(betas): point config at derivatives/betas/** (right metadata.csv); was auto-globbing fmriprep tree and crashing the Nifti decoder on .json sidecars

README.md

@@ -14,8 +14,11 @@ size_categories:
   - 1K<n<10K
 configs:
   - config_name: betas
-    description: "Individual condition beta maps (NIfTI) with subject and condition labels"
+    description: "Beta maps (individual condition + all-condition stacked) with subject, condition, and type labels"
     default: true
+    data_files:
+      - split: train
+        path: derivatives/betas/**
   - config_name: betas_stacked
     description: "All-condition stacked beta volumes per subject (NIfTI)"
   - config_name: events