Add Robotics tag and metadata

Hi! I'm VB from Hugging Face. Congratulations on your model! I'm opening a quick PR to update the model card to add Robotics metadata.

This PR adds standard Robotics metadata to the model card:
- Added 'Robotics' to tags
- Set pipeline_tag to 'robotics'

These changes help improve discoverability of robotics-related models on the Hugging Face Hub.

README.md

@@ -63,4 +63,4 @@ python lerobot/scripts/eval.py \
     --use_amp=false
 ```
 
-The original code was heavily refactored, and some bugs were spotted along the way. The differences in code may account for the difference in success rate. Another possibility is that our simulation environment may use slightly different heuristics to evaluate success (we've observed that success is registered as soon as the second arm's gripper makes antipodal contact with the cube). Finally, one should observe that the in-training evaluation jumps up towards the end of training. This may need further investigation (Is it statistically significant? If so, what is the cause?).
+The original code was heavily refactored, and some bugs were spotted along the way. The differences in code may account for the difference in success rate. Another possibility is that our simulation environment may use slightly different heuristics to evaluate success (we've observed that success is registered as soon as the second arm's gripper makes antipodal contact with the cube). Finally, one should observe that the in-training evaluation jumps up towards the end of training. This may need further investigation (Is it statistically significant? If so, what is the cause?).