DiffusionNFT: Online Diffusion Reinforcement with Forward Process - Zheng, Kaiwen; Chen, Huayu; Ye, Haotian; Wang, Haoxiang; Zhang, Qinsheng; Jiang, Kai; Su, Hang; Ermon, Stefano; Zhu, Jun; Liu, Ming-Yu (International Conference on Learning Representations, 2026)