Iteration-1 plan for spec 0030 (the single-run side): two tasks.
- Task 1 (aura-engine): BindError vocabulary, the shared `resolve` core
(two-phase total error order), Composite::with / Binder / Binder::bootstrap,
the lib.rs re-export, and the engine tests (resolve round-trip, one per
single-run BindError variant, two precedence tests, the C1 named≡positional
equivalence test). RED-first via a todo!() resolve stub, GREEN on impl.
- Task 2 (aura-cli): convert the sample single-run test to .with(...).bootstrap()
using the exact param_space() names (sma_cross.fast/sma_cross.slow/scale).
The full BindError enum (incl. EmptyAxis) is defined now and re-exported, so the
unconstructed sweep-only variant is reachable API (not dead_code) — EmptyAxis is
constructed in iteration 2. Engine core untouched (C1/C12/C19/C23).
refs #35
