Establishes the first functional, developer-focused release of cheq. This version delivers a robust, pure Rust library that provides a complete and accurate implementation of the Rappé-Goddard Charge Equilibration (QEq) model. The core library now includes all fundamental components: a type-safe API for molecular systems, a file-based, extensible engine for atomic parameters, and a high-precision solver that performs self-consistent field (SCF) iterations for systems containing hydrogen. Critically, the underlying electrostatic interactions are calculated from first principles using exact analytical formulas for two-center Coulomb integrals between Slater-type orbitals, ensuring maximum fidelity to the original QEq theory. This milestone provides a powerful, high-performance, and standalone building block for developers to dynamically assign geometry-dependent partial charges to any molecular structure, paving the way for advanced molecular dynamics and materials science simulations.