[model] add Qwen2.5-Omni model (#7537)

* preserve image_sizes

* preserve image_sizes

* init plugin

* support audio-text2text lora

* nit

* support image/video-text2text, audio-text2text

* remove args

* remove lines

* add docs && nit

* remove some comments

* fix && add merge part script

* add license

src/llamafactory/data/template.py

@@ -1367,6 +1367,24 @@ register_template(
 )
 
 
+# copied from qwen template
+register_template(
+    name="qwen2_omni",
+    format_user=StringFormatter(slots=["<|im_start|>user\n{{content}}<|im_end|>\n<|im_start|>assistant\n"]),
+    format_assistant=StringFormatter(slots=["{{content}}<|im_end|>\n"]),
+    format_system=StringFormatter(slots=["<|im_start|>system\n{{content}}<|im_end|>\n"]),
+    format_function=FunctionFormatter(slots=["{{content}}<|im_end|>\n"], tool_format="qwen"),
+    format_observation=StringFormatter(
+        slots=["<|im_start|>user\n<tool_response>\n{{content}}\n</tool_response><|im_end|>\n<|im_start|>assistant\n"]
+    ),
+    format_tools=ToolFormatter(tool_format="qwen"),
+    default_system="You are a helpful assistant.",
+    stop_words=["<|im_end|>"],
+    mm_plugin=get_mm_plugin(
+        name="qwen2_omni", audio_token="<|AUDIO|>", image_token="<|IMAGE|>", video_token="<|VIDEO|>"
+    ),
+)
+
 # copied from qwen template
 register_template(
     name="qwen2_vl",