This PR improves the model card for `UnifiedReward-qwen-7b`, clarifying its role as a reward model in the context of the **Pref-GRPO: Pairwise Preference Reward-based GRPO for Stable Text-to-Image Reinforcement Learning** paper.
Specifically, it addresses the following points:
- **Corrected Paper Link:** Updated the paper link in the content to [https://huggingface.co/papers/2508.20751](https://huggingface.co/papers/2508.20751) as per the prompt's instruction, which describes the Pref-GRPO framework in which this reward model is used.
- **Updated Project Page Link:** Pointed the project page to the more specific [https://codegoat24.github.io/UnifiedReward/Pref-GRPO](https://codegoat24.github.io/UnifiedReward/Pref-GRPO).
- **Added GitHub Link:** Included a direct link to the Pref-GRPO code at [https://github.com/CodeGoat24/Pref-GRPO](https://github.com/CodeGoat24/Pref-GRPO).
- **Added Pipeline Tag:** Set `pipeline_tag: image-text-to-text` to accurately reflect the model's input…
