feat: Add chat template

got it from https://huggingface.co/microsoft/phi-4/blob/main/tokenizer_config.json

tokenizer_config.json

@@ -319,5 +319,6 @@
   "eos_token": "<|endoftext|>",
   "model_max_length": 2048,
   "tokenizer_class": "CodeGenTokenizer",
-  "unk_token": "<|endoftext|>"
+  "unk_token": "<|endoftext|>",
+  "chat_template": "{% for message in messages %}{% if (message['role'] == 'system') %}{{'<|im_start|>system<|im_sep|>' + message['content'] + '<|im_end|>'}}{% elif (message['role'] == 'user') %}{{'<|im_start|>user<|im_sep|>' + message['content'] + '<|im_end|>'}}{% elif (message['role'] == 'assistant') %}{{'<|im_start|>assistant<|im_sep|>' + message['content'] + '<|im_end|>'}}{% endif %}{% endfor %}{% if add_generation_prompt %}{{ '<|im_start|>assistant<|im_sep|>' }}{% endif %}"
 }