//! Existence oracle strategies.
//!
//! Each submodule groups strategies by detection vector.
//! `default_chain_registry` combines all per-vector registries.
/// Builds the full producer/consumer `ChainRegistry` for all existence vectors.
///
/// Combines cache-probing (7 edges), redirect-diff (8 edges), and
/// status-code-diff (6 edges) registries — 21 edges total.