//! bird library surface — internal test infrastructure only.
//!
//! bird is distributed as a binary; the library surface is unstable and
//! intended for internal test infrastructure only. External consumers should
//! shell out to the `bird` binary, not import this crate.
//!
//! Concrete invocation patterns — `run_argv`, `run_with_paths` against a
//! `TempDir`-backed `ResolvedPaths`, captured writers, parsed JSON
//! envelopes, parallel fixtures — live under `examples/` and mirror the
//! shapes used by `tests/common/mod.rs` and `tests/parallel_run.rs`. They
//! are reference code for someone debugging the in-process test surface,
//! not an endorsement of the library as a downstream API.