Improve model card: add metadata, library name, and paper/code links

Hi! I'm Niels from the community science team at Hugging Face.

This PR improves the model card for CharacterShot. Key changes include:
- Adding the `pipeline_tag: image-to-video` and `library_name: diffusers` metadata to ensure the model is discoverable and provides the correct code snippets.
- Adding links to the paper and the official GitHub repository.
- Providing a concise summary of the framework and a BibTeX citation.

Please let me know if you have any questions!

README.md

@@ -1,4 +1,37 @@
 ---
 license: mit
+library_name: diffusers
+pipeline_tag: image-to-video
+tags:
+- character-animation
+- 4d
+- image-to-video
 ---
-arxiv.org/abs/2508.07409
+---
+
+# CharacterShot: Controllable and Consistent 4D Character Animation
+
+[**CharacterShot**](https://arxiv.org/abs/2508.07409) is a controllable and consistent 4D character animation framework that enables the creation of dynamic 3D characters (i.e., 4D character animation) from a single reference character image and a 2D pose sequence. 
+
+- **Paper:** [CharacterShot: Controllable and Consistent 4D Character Animation](https://arxiv.org/abs/2508.07409)
+- **Repository:** [https://github.com/Jeoyal/CharacterShot](https://github.com/Jeoyal/CharacterShot)
+
+## Introduction
+
+CharacterShot utilizes a powerful 2D character animation model based on a DiT image-to-video architecture. It lifts these animations to 3D using dual-attention modules and camera priors to ensure spatial-temporal and spatial-view consistency. The final representation is optimized using neighbor-constrained 4D Gaussian Splatting, resulting in stable and continuous character representations.
+
+The model was trained on **Character4D**, a large-scale dataset containing 13,115 unique characters with diverse appearances and motions.
+
+## Citation
+
+```bibtex
+@article{gao2025charactershot,
+  title={CharacterShot: Controllable and Consistent 4D Character Animation},
+  author={Gao, Junyao and Li, Jiaxing and Liu, Wenran and Zeng, Yanhong and Shen, Fei and Chen, Kai and Sun, Yanan and Zhao, Cairong},
+  journal={arXiv preprint arXiv:2508.07409},
+  year={2025}
+}
+```
+
+## Acknowledgements
+The code is built upon [CogVideo](https://github.com/THUDM/CogVideo).