This PR adds a comprehensive model card for the **SphereAR** model.
It includes:
- A link to the paper [Hyperspherical Latents Improve Continuous-Token Autoregressive Generation](https://huggingface.co/papers/2509.24335).
- The `pipeline_tag: text-to-image` to ensure discoverability for image generation tasks on the Hugging Face Hub.
- A link to the official GitHub repository for more details and code.
- A table of available model checkpoints and their reported performance.
