[train] KTransformers SFT as backend engine for LLaMA-Factory (#9400)

Co-authored-by: jimmy128 <jimmy128@noreply.gitcode.com>
Co-authored-by: Yaowei Zheng <hiyouga@buaa.edu.cn>

src/llamafactory/extras/constants.py

@@ -120,6 +120,7 @@ class EngineName(str, Enum):
     HF = "huggingface"
     VLLM = "vllm"
     SGLANG = "sglang"
+    KT = "ktransformers"
 
 
 class DownloadSource(str, Enum):