Add task category to dataset card

This PR adds the missing `task_categories` metadata to the dataset card, making it discoverable under the `robotics` category on the Hub. The existing comprehensive documentation remains unchanged.

README.md

@@ -1,12 +1,14 @@
 ---
 license: apache-2.0
+pretty_name: Orbit-Planner Orbital Evasion Dataset
+task_categories:
+- robotics
 tags:
 - '- spacecraft'
 - '- obstacle-avoidance'
 - '- world-models'
 - '- isaac-sim'
 - '- trajectory-prediction'
-pretty_name: Orbit-Planner Orbital Evasion Dataset
 ---
 
 # Orbit-Planner Orbital Evasion Dataset
@@ -171,4 +173,4 @@ If you use this dataset in your research, please cite our
   journal = {arXiv preprint arXiv:2608.16651},
   year    = {2026}
 }
-```
+```