Add `library_name` and `pipeline_tag` to model card

This PR improves the model card by adding the `library_name` and `pipeline_tag` to the metadata.

- `library_name: transformers` ensures that the model is recognized as compatible with the Hugging Face Transformers library, enabling the automated "how to use" widget.
- `pipeline_tag: text-generation` categorizes the model correctly, making it discoverable for users browsing text generation models on the Hub.

No changes were made to the existing descriptive content, which already provides comprehensive information, including the paper link, code repository, project page, and usage examples.

README.md

@@ -1,9 +1,11 @@
 ---
-license: apache-2.0
-language:
-- en
 base_model:
 - Qwen/Qwen2.5-7B-Instruct
+language:
+- en
+license: apache-2.0
+library_name: transformers
+pipeline_tag: text-generation
 ---
 
 # Fast-dLLM v2 (7B) — Efficient Block-Diffusion LLM