//! Module: validate
//!
//! Responsibility: module-local ownership and contracts for validate.
//! Does not own: cross-module orchestration outside this module.
//! Boundary: exposes this module API while keeping implementation details internal.
use crate::;
///
/// validate
/// Validate a visitable tree, collecting issues by path.
///
/// Validation is non-failing at the traversal level. All validation
/// issues are collected and returned to the caller, which may choose
/// how to interpret them.
///