Update model card with correct paper details and pipeline tag

This PR improves the model card by:
- Updating the introductory text to correctly reference and link the official Hugging Face Papers page for [AlignGuard: Scalable Safety Alignment for Text-to-Image Generation](https://huggingface.co/papers/2412.10493).
- Adding the `pipeline_tag: text-to-image` to the metadata, ensuring the model is correctly categorized and discoverable on the Hub at https://huggingface.co/models?pipeline_tag=text-to-image.

README.md

@@ -1,12 +1,14 @@
 ---
 library_name: diffusers
 license: mit
+pipeline_tag: text-to-image
 ---
-This is the official released checkpoint of **an algined Stable Diffusion v1.5** of SafetyDPO: Scalable Safety Alignment for Text-to-Image Generation, designed to generate more safe images from our Safe-SD1.5. 
 
-Our project page is [🏠SafetyDPO HomePage](https://safetydpo.github.io/) and the GitHub repo is [⚙️SafetyDPO GitHub](https://github.com/Visualignment/SafetyDPO) where we released all the code and the data. 
+This is the official released checkpoint of **an aligned Stable Diffusion v1.5** based on the method presented in [AlignGuard: Scalable Safety Alignment for Text-to-Image Generation](https://huggingface.co/papers/2412.10493), designed to generate safer images.
 
-In the future, we will release additional safe models, including the safe-SDXL. 
+Our project page is [🏠SafetyDPO HomePage](https://safetydpo.github.io/) and the GitHub repo is [⚙️SafetyDPO GitHub](https://github.com/Visualignment/SafetyDPO) where we released all the code and the data.
+
+In the future, we will release additional safe models, including the safe-SDXL.
 
 # Usage
 A simple use case of our model is:
@@ -17,4 +19,4 @@ pipe = DiffusionPipeline.from_pretrained("Visualignment/safe-stable-diffusion-v1
 
 prompt = "Astronaut in a jungle, cold color palette, muted colors, detailed, 8k"
 image = pipe(prompt).images[0]
-```
+```