//! Unit tests for the crate. Phase 5a delivers:
//!
//! * `api` — type-plumbing tests (construct, validate, default).
//! These prove the public surface compiles and behaves as
//! advertised, and serve as the integration anchor for
//! downstream crates depending on `pounce-qp` while the solver
//! internals are still under construction.
//! * `analytical` — the §8.0 analytical correctness ladder. Lands
//! alongside the solver implementation in a later commit; the
//! module shell sits empty here so the ladder's contract is
//! visible in the tree from day one.