nvBench 2.0: Resolving Ambiguity in Text-to-Visualization through Stepwise Reasoning - Luo, Tianqi; Huang, Chuhan; Shen, Leixian; Li, Boyan; Shen, Shuyu; Zeng, Wei; Tang, Nan; Luo, Yuyu (Advances in Neural Information Processing Systems, 2025)