Improve model card: Add pipeline tag and GitHub link

This PR improves the model card by:
- Adding the `pipeline_tag: image-classification` to the metadata, making the model discoverable under the image classification pipeline on Hugging Face.
- Adding an explicit link to the paper: [Is Artificial Intelligence Generated Image Detection a Solved Problem?](https://huggingface.co/papers/2505.12335)
- Adding an explicit link to the GitHub repository for the code: [https://github.com/HorizonTEL/AIGIBench](https://github.com/HorizonTEL/AIGIBench).

README.md

@@ -1,8 +1,10 @@
 ---
-license: cc-by-nc-sa-4.0
 datasets:
 - HorizonTEL/AIGIBench
+license: cc-by-nc-sa-4.0
+pipeline_tag: image-classification
 ---
+
 <div align="center">
  <br>
 <h1>Is Artificial Intelligence Generated Image Detection a Solved Problem?</h1>
@@ -22,6 +24,10 @@ datasets:
 
 **This repository is the official pre-trained checkpoints of the AIGIBench in Setting-II**: Training on 144K images generated by both SD-v1.4 and ProGAN, covering the same four object categories.
 
+Find the associated paper here: [Is Artificial Intelligence Generated Image Detection a Solved Problem?](https://huggingface.co/papers/2505.12335)
+
+The code for the project can be found on GitHub: [https://github.com/HorizonTEL/AIGIBench](https://github.com/HorizonTEL/AIGIBench)
+
 If this project helps you, please fork, watch, and give a star to this repository.  
 
 ## Contact