Improve model card: add metadata and introductory links

This PR enhances the model card by:

- Adding the `pipeline_tag: text-to-3d`, which ensures the model is discoverable under relevant tasks on the Hub.
- Specifying `library_name: transformers` as the model can be loaded and used via the Hugging Face Transformers library.
- Setting the `license` tag to `other`, as the "NVIDIA Open Model License" is a custom license not listed in SPDX identifiers. The full license details are retained in the markdown content.
- Adding a new introductory sentence that links directly to the Hugging Face Paper page for easy access to the research.
- Adding a clear link to the main GitHub repository for code access.

Please review and merge if everything looks good!

README.md

@@ -1,3 +1,13 @@
+---
+pipeline_tag: text-to-3d
+library_name: transformers
+license: other
+---
+
+This repository contains the DiffusionText2WorldGeneration model, part of the [Cosmos World Foundation Model Platform for Physical AI](https://huggingface.co/papers/2501.03575).
+
+Code: https://github.com/NVIDIA/Cosmos
+
 ## How to Use
 
 ```python
@@ -95,4 +105,4 @@ This project will download and install additional third-party open source softwa
 
 NVIDIA Cosmos source code is released under the [Apache 2 License](https://www.apache.org/licenses/LICENSE-2.0).
 
-NVIDIA Cosmos models are released under the [NVIDIA Open Model License](https://www.nvidia.com/en-us/agreements/enterprise-software/nvidia-open-model-license). For a custom license, please contact [cosmos-license@nvidia.com](mailto:cosmos-license@nvidia.com).
+NVIDIA Cosmos models are released under the [NVIDIA Open Model License](https://www.nvidia.com/en-us/agreements/enterprise-software/nvidia-open-model-license). For a custom license, please contact [cosmos-license@nvidia.com](mailto:cosmos-license@nvidia.com).