Add task category and tags to dataset card

This PR improves the discoverability and categorization of the `FluidNexus` dataset by adding relevant metadata:
- `task_categories: image-to-3d`
- `tags`: `3d-reconstruction`, `fluid-dynamics`, `video-to-3d`, and `physics-simulation`

These additions provide clearer information about the dataset's domain and the AI task it addresses.

README.md

@@ -1,6 +1,14 @@
 ---
 license: mit
+task_categories:
+- image-to-3d
+tags:
+- 3d-reconstruction
+- fluid-dynamics
+- video-to-3d
+- physics-simulation
 ---
+
 # FluidNexus: 3D Fluid Reconstruction and Prediction From a Single Video
 
 
@@ -42,4 +50,4 @@ If you find these datasets useful for your research, please cite our paper:
     month     = {June},
     year      = {2025},
 }
-```
+```