Improve model card with metadata and description

Hi! I'm Niels, part of the community science team at Hugging Face.

This PR improves the model card for this repository by:
- Adding `library_name: transformers` and `pipeline_tag: text-generation` to the metadata for better discoverability and to enable the "how to use" widget.
- Adding a model description that links to the associated research paper: [Mix Data or Merge Models? Balancing the Helpfulness, Honesty, and Harmlessness of Large Language Model via Model Merging](https://huggingface.co/papers/2502.06876).
- Highlighting the core methodology used (RESM merging).

This helps users understand the context and technical details of the model.

README.md

@@ -1,14 +1,28 @@
 ---
-license: apache-2.0
 base_model:
 - mistralai/Mistral-7B-Instruct-v0.2
+license: apache-2.0
+library_name: transformers
+pipeline_tag: text-generation
 ---
 
+# Mistral-7B-RESM
+
+This model is a 3H-aligned Large Language Model (LLM) developed as part of the research paper [Mix Data or Merge Models? Balancing the Helpfulness, Honesty, and Harmlessness of Large Language Model via Model Merging](https://huggingface.co/papers/2502.06876).
+
+## Model Description
+
+Mistral-7B-RESM is based on [Mistral-7B-Instruct-v0.2](https://huggingface.co/mistralai/Mistral-7B-Instruct-v0.2) and was optimized across three critical dimensions: **Helpfulness, Honesty, and Harmlessness (3H optimization)**. 
+
+The model was created using a novel parameter-level merging strategy called **RESM** (**R**eweighting **E**nhanced task **S**ingular **M**erging). RESM addresses challenges in 3H-aligned LLM merging, such as preference noise accumulation and layer sparsity adaptation, through outlier weighting and sparsity-aware rank selection strategies.
+
 ## Citation
-```
+
+```bibtex
 @article{yang2025mix,
   title={Mix Data or Merge Models? Balancing the Helpfulness, Honesty, and Harmlessness of Large Language Model via Model Merging},
   author={Yang, Jinluan and Jin, Dingnan and Tang, Anke and Shen, Li and Zhu, Didi and Chen, Zhengyu and Wang, Daixin and Cui, Qing and Zhang, Zhiqiang and Zhou, Jun and others},
   journal={arXiv preprint arXiv:2502.06876},
   year={2025}
-}
+}
+```