XDL离线训练只生成item_emb一个文件

XDL离线训练产出模型会针对Serving产出四个文件dense.txt、graph.txt、item_emb、sparse.txt，问下这个功能大概什么时候能出呀？ 谢了！

Start by locating the offline-training and Serving-related entry points that produce item_emb, then trace whether dense.txt, graph.txt, and sparse.txt are handled anywhere. Compare the current output with the four files requested in the issue; done means the offline model produces all four Serving files, with tests or documented verification for each output.

Written by the indexing model from the issue text.