Add rai:hasSyntheticData field (NeurIPS RAI requirement)

croissant.json

@@ -62,6 +62,7 @@
   "isLiveDataset": false,
   "rai:dataCollection": "Fully synthetic. Every instance is procedurally produced by a deterministic per-task generator that consumes only released task definitions and a seed. There is no scraping, no human subjects, no third-party media, and no annotation of pre-existing content. Generators run as released code; instance manifests record the seed, the generator version, and per-task tolerances for exact reproduction.",
   "rai:dataCollectionType": ["Synthetic"],
+  "rai:hasSyntheticData": true,
   "rai:dataPreprocessingProtocol": "No post-collection preprocessing is applied. Each task's generator emits the five-artifact contract (first_frame.png, prompt.txt, final_frame.png, ground_truth.mp4, question_metadata.json) directly. Sample index, seed, and version are recorded in question_metadata.json so any instance is regenerable from the released code.",
   "rai:dataAnnotationProtocol": "No human annotation. The reference rollout (ground_truth.mp4) is computed by the generator's deterministic ground-truth solver and is not produced by humans.",
   "rai:dataAnnotationPlatform": "N/A (no annotation).",