//! MoQT intercepting proxy — transparent stream forwarding with inline
//! frame parsing and observation.
//!
//! This crate provides a transparent proxy that sits between a MoQT client
//! and relay, forwarding all bytes bidirectionally while parsing MoQT frames
//! inline to emit structured events. It does not participate in MoQT state
//! management — it observes and optionally mutates, but never acts as an
//! endpoint.