Probabilistic Simulation of Single-Entity Systems in Irregular Time // A foundation for probabilistic simulation of single- entity systems in which events occur at irregular times and each event updates only a small, sparse subset of the entity's state. Models are assembled from a declared schema and a 'ModelBundle' of callback functions (event proposal, state transition, stopping rule) and run through a single validated entry point, 'load_model()'. Supports competing event processes, schema-declared decision points with user-supplied policies, typed parameter draws for representing uncertainty, and optional trajectory recording for auditing simulated decisions. Designed to be domain agnostic: this package contains no model of any particular system, only the scaffolding for building one.