//! Core standard library for clojurust (`clojure.core` equivalent).
//!
//! Phase 5 will implement:
//! - Arithmetic, comparison, and type-predicate functions
//! - Persistent collection operations and seq abstractions
//! - Higher-order functions (`map`, `filter`, `reduce`, …)
//! - Lazy sequences, I/O, string utilities
//! - Core macros (`when`, `cond`, `->`, `for`, …)
//! - Concurrency primitives (atom, ref/STM, agent, future) — Phase 7