Improve model card: title, metadata, project page

This PR addresses several improvements for the model card:
- Corrects the main title to "Step-Audio 2 Technical Report".
- Adds `pipeline_tag: any-to-any` to the metadata, ensuring the model is discoverable under this modality.
- Includes `library_name: transformers` in the metadata, enabling direct integration and "how to use" widgets on the Hub.
- Adds clear, explicit links to the paper, official project page, and code repository for better visibility and user experience.

README.md

@@ -1,5 +1,7 @@
 ---
 license: apache-2.0
+pipeline_tag: any-to-any
+library_name: transformers
 ---
 
 <div align="center">
@@ -21,6 +23,12 @@ license: apache-2.0
   <a href="https://github.com/stepfun-ai/Step-Audio2/blob/main/LICENSE"><img alt="License" src="https://img.shields.io/badge/License-Apache%202.0-blue?&color=blue"/></a>
 </div>
 
+# Step-Audio 2 Technical Report
+
+**Paper**: [Step-Audio 2 Technical Report](https://arxiv.org/abs/2507.16632)
+**Project Page**: [Step-Audio 2 Documentation](https://www.stepfun.com/docs/en/step-audio2)
+**Code**: [GitHub Repository](https://github.com/stepfun-ai/Step-Audio2)
+
 ## Introduction
 
 
@@ -133,7 +141,7 @@ CER for Chinese, Cantonese and Japanese and WER for Arabian and English. N/A ind
       <td align="center"><strong>2.71</strong></td>
       <td align="center">4.47</td>
       <td align="center">5.05</td>
-      <td align="center">3.03</td>
+      <align="center">3.03</align>
       <td align="center">3.05</td>
     </tr>
     <tr>
@@ -190,6 +198,7 @@ CER for Chinese, Cantonese and Japanese and WER for Arabian and English. N/A ind
       <td align="center">7.01</td>
       <td align="center">2.68</td>
       <td align="center"><strong>2.53</strong></td>
+      <td align="center">2.53</td>
     </tr>
     <tr>
       <td align="left">KeSpeech phase1</td>
@@ -854,3 +863,7 @@ The model and code in the repository is licensed under [Apache 2.0](LICENSE) Lic
       url={https://arxiv.org/abs/2507.16632},
 }
 ```
+
+## Star History
+
+[![Star History Chart](https://api.star-history.com/svg?repos=stepfun-ai/Step-Audio2&type=Date)](https://star-history.com/#stepfun-ai/Step-Audio2&Date)