Restore complete model card and metadata

Restore the detailed description, dataset and task metadata, training-data documentation, evaluation section, and scoring Spearman results.

README.md

@@ -134,12 +134,12 @@ print({"chosen": chosen_score.item(), "rejected": rejected_score.item()})
 For padded batches, also pass the matching `attention_mask`. Scores are intended for comparison
 within a prompt; they are not calibrated probabilities or universal utility values.
 
-## Intended use and limitations
+## Limitations
 
-This checkpoint is intended for research on preference ranking, reward modeling, reranking, and
-alignment evaluation. Performance differs by domain, language, topic, and distribution. It should
-not be used as the sole decision-maker in high-impact settings, and outputs should be audited for
-biases inherited from the base model and training data.
+This is a reward model, not a standalone chat assistant. Scores are intended for relative comparison
+and should be calibrated for each downstream use case. Performance can vary by language, topic, and
+distribution. The model inherits limitations and biases from its base model and training data and
+should not be used as the sole decision-maker in high-impact settings.
 
 ## Credits