Improve dataset card: Add task category, license, and tags

This PR improves the dataset card by adding crucial metadata to enhance its discoverability and provide more context:
- Adds `task_categories: visual-document-retrieval` to accurately classify the dataset's primary task.
- Specifies `license: cc-by-nc-4.0`.
- Includes `library_name: transformers`, as the dataset is intended for use with models often built and used with the Hugging Face Transformers library.
- Adds relevant `tags`: `multimodal`, `embeddings`, `pretraining`, `document-retrieval`, and `interleaved-data` to better describe the dataset's nature and application.

The existing `dataset_info` and `configs` metadata have been preserved. No changes were made to the existing paper, code, or project links in the markdown content.

README.md

@@ -16,7 +16,19 @@ configs:
   data_files:
   - split: train
     path: data/train-*
+task_categories:
+- visual-document-retrieval
+license: cc-by-nc-4.0
+library_name:
+- transformers
+tags:
+- multimodal
+- embeddings
+- pretraining
+- document-retrieval
+- interleaved-data
 ---
+
 # Copali train split used in MoCa Continual Pre-training
 
 [🏠 Homepage](https://haon-chen.github.io/MoCa/) | [💻 Code](https://github.com/haon-chen/MoCa) | [🤖 MoCa-Qwen25VL-7B](https://huggingface.co/moca-embed/MoCa-Qwen25VL-7B) | [🤖 MoCa-Qwen25VL-3B](https://huggingface.co/moca-embed/MoCa-Qwen25VL-3B) | [📚 Datasets](https://huggingface.co/moca-embed/datasets) | [📄 Paper](https://arxiv.org/abs/2506.23115)