Refines cheq into a dual-mode precision instrument. This release introduces exact Slater-Type Orbital (STO) integration, eliminating Gaussian approximation errors for users demanding strict adherence to the Rappé–Goddard formalism. By making the integral method configurable, cheq now supports both high-throughput approximation (GTO) and ground-truth accuracy (STO). This milestone also establishes a rigorous benchmarking suite to quantify the speed-accuracy trade-off, ensuring the solver remains the definitive reference implementation for QEq physics.