Atom‐in‐Molecule Analysis, Density Function Theory Research, Spectroscopy, Charge Transfer, and (Static, Dynamic) Nonlinear Optical Effects of (Z)4,4′‐Bis[‐3‐N‐Ethyl‐2‐N’‐(Phenylimino) Thiazolidin‐4‐One] Methane (ChemistryOpen, 2026)