Improve model card: Add pipeline tag, library name, and paper link

This PR enhances the model card by:
- Adding `library_name: transformers` to enable the automated "how to use" widget, based on `config.json` and `tokenizer_config.json` which indicate compatibility with the Transformers library.
- Adding `pipeline_tag: text-generation` to improve discoverability for LLM models.
- Including a direct link to the paper: [Co-rewarding: Stable Self-supervised RL for Eliciting Reasoning in Large Language Models](https://huggingface.co/papers/2508.00410).

README.md

@@ -1,8 +1,11 @@
 ---
 license: mit
+library_name: transformers
+pipeline_tag: text-generation
 ---
+
 ### Entropy Minimization: Qwen3-4B-Base trained on OpenRS
 
-This is the Qwen3-4B-Base model trained by Entropy Minimization using OpenRS training set.
+This is the Qwen3-4B-Base model trained by Entropy Minimization using OpenRS training set, as presented in the paper [Co-rewarding: Stable Self-supervised RL for Eliciting Reasoning in Large Language Models](https://huggingface.co/papers/2508.00410).
 
 If you are interested in Co-rewarding, you can find more details on our Github Repo [https://github.com/tmlr-group/Co-rewarding].