Add guidance free method as GFT

[Bili-Sakura]

Source code: https://github.com/thu-ml/GFT
Paper: Chen, Huayu, Kai Jiang, Kaiwen Zheng, Jianfei Chen, Hang Su, and Jun Zhu. “Visual Generation Without Guidance,” 2025. ICML, https://openreview.net/forum?id=gM6aboVgTO.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the contributing guidelines are likely to be ignored.