3D‐Printed Adiabatic Jet Ignition Pre‐Chambers for High‐Efficiency, Low‐Emission Hydrogen Engines: A Narrative Review of Progress, Performance Benchmarks, and Additive Manufacturing Pathways. - Boretti, Alberto; Geng, Tom; Huang, Lei; Tian, Yang; Liu, Fei‐Yang (Applied Research, 2026)