Update metadata: add pipeline tag and remove arXiv tag from YAML

This PR updates the model card metadata to follow the Hugging Face guidelines:

- Adds `pipeline_tag: robotics` so the model is discoverable under the correct category.
- Removes the `arxiv:2609.39685` entry from the YAML `tags` list, since arXiv IDs should not appear in metadata. The paper is still linked in the markdown content.

No `library_name` is added, since the model uses a custom `coachworld` implementation and does not claim compatibility with standard libraries such as Transformers or Diffusers. No license is added because the model weights' terms are not specified (the README notes that weights and datasets have their own terms). The content section is left unchanged.

README.md

@@ -1,11 +1,11 @@
 ---
 tags:
-  - robotics
-  - world-model
-  - action-conditioned-video-generation
-  - robot-manipulation
-  - coachworld
-  - arxiv:2609.39685
+- robotics
+- world-model
+- action-conditioned-video-generation
+- robot-manipulation
+- coachworld
+pipeline_tag: robotics
 ---
 
 # CoachWorld — Pretrained Robot World Model