Add pipeline tag: text-generation

This PR adds the `pipeline_tag: text-generation` to the model card metadata. This ensures the model is correctly categorized and discoverable on the Hugging Face Hub via the relevant pipeline tag. The model is a text generation model, as indicated by the abstract and the sample usage in the README.

README.md

@@ -1,8 +1,10 @@
 ---
-library_name: transformers
-license: apache-2.0
 base_model:
 - Qwen/Qwen2.5-32B-Instruct
+datasets:
+- open-thoughts/open-thoughts-114k
+library_name: transformers
+license: apache-2.0
 tags:
 - llama-factory
 - full
@@ -10,8 +12,7 @@ tags:
 model-index:
 - name: OpenThinker-32B
   results: []
-datasets:
-- open-thoughts/open-thoughts-114k
+pipeline_tag: text-generation
 ---
 
 <p align="center">