Phase 1: Compatibility skeleton complete. Native-Rust forensic reimplementation of libxml2+libxslt with C ABI drop-in replacement. 62 tests passing, ABI courts verified, C headers compatible, Docker oracle built.
//! RELAX NG implementation (§27, §85 Phase 6).
//!//! RELAX NG schema validation. libxml2's RELAX NG support is known to be
//! incomplete/non-conformant in places — parity follows the oracle.
//!//! Phase 0: scaffolded. Implementation begins in Phase 6.