Why Reasoning Fails to Plan: A Planning-Centric Analysis of Long-Horizon Decision Making in LLM Agents. - Zehong Wang; Fang Wu 002; Hongru Wang 016; Xiangru Tang; Bolian Li; Zhenfei Yin; Yijun Ma; Yiyang Li; Weixiang Sun; Xiusi Chen; Yanfang Ye 001 (CoRR, 2026)