Improve model card: Add paper and code badges, update datasets metadata

Hi! This PR enhances the model card for `PIPer-8B` by:
- Adding prominent badges for the associated paper ([PIPer: On-Device Environment Setup via Online Reinforcement Learning](https://huggingface.co/papers/2509.25455)) and the main GitHub repository (`https://github.com/JetBrains-Research/PIPer`) for better visibility and quick access.
- Updating the `datasets` metadata to include all three relevant datasets mentioned in the "Available Artifacts" section of the model card.

All other existing metadata (`base_model`, `library_name`, `license`, `pipeline_tag`) and the comprehensive Markdown content (including the "Reproduce the results" section) are kept as they are accurate and well-structured. No sample usage for inference was added as no such snippet was found in the GitHub README that is directly compatible with the model and `transformers` library.

README.md

@@ -1,12 +1,15 @@
 ---
-library_name: transformers
-datasets:
-- JetBrains-Research/envbench-zeroshot-rl
 base_model:
 - JetBrains-Research/Qwen3-8B-am
-pipeline_tag: text-generation
+datasets:
+- JetBrains-Research/PIPer-envbench-zeroshot-rl
+- JetBrains-Research/PIPer-SFT-2500-sharegpt
+- JetBrains-Research/PIPer-eval
+library_name: transformers
 license: mit
+pipeline_tag: text-generation
 ---
+
 <img src="https://github.com/JetBrains-Research/PIPer/blob/main/misc/piper-logo.png?raw=true" alt="PIPer Mascot" style="height: 6em">
 <h1>
   PIPer: On-Device Environment Setup via Online Reinforcement Learning
@@ -15,6 +18,8 @@ license: mit
 
 <div align="center">
 
+[![Paper](https://img.shields.io/badge/📖-Paper-b31b1b.svg)](https://huggingface.co/papers/2509.25455)
+[![Code](https://img.shields.io/badge/💻-Code-blue.svg)](https://github.com/JetBrains-Research/PIPer)
 [![Models](https://img.shields.io/badge/🤗%20Hugging%20Face-Models-orange.svg)](https://jb.gg/PIPer)
 [![Dataset](https://img.shields.io/badge/🤗%20Hugging%20Face-Dataset-green.svg)](https://huggingface.co/datasets/JetBrains-Research/PIPer-envbench-zeroshot-rl)
 [![License](https://img.shields.io/badge/License-MIT-red.svg)](LICENSE)
@@ -96,4 +101,4 @@ uv run piper/hparams_entrypoint.py +experiment=llm-reward --info config
 
 ## 📄 License
 
-This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.
+This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.