Add pipeline tag to metadata

This PR adds the `pipeline_tag: other` to the YAML metadata of the model card. This helps classify the repository properly on the Hugging Face Hub under the "Other" task category, as it is a specialized HMM checkpoint repository for constrained decoding rather than a standard language model.

README.md

@@ -1,4 +1,5 @@
 ---
+pipeline_tag: other
 tags:
 - deco-g
 - hmm
@@ -18,4 +19,4 @@ The code release at https://github.com/haikangdeng/deco-g downloads these checkp
 | `qwen7b` | `Qwen/Qwen2.5-7B-Instruct` | `qwen2.5-7b-instruct` |
 | `qwen3-8b` | `Qwen/Qwen3-8B` | `qwen3-8b` |
 
-Each subfolder contains a `config.json` and `model.safetensors` compatible with Deco-G's `HMM` class.
+Each subfolder contains a `config.json` and `model.safetensors` compatible with Deco-G's `HMM` class.