spec-fuzz

Turn Fuzz-kind obligations into runnable fuzz targets. Consumes quoin advise --json, selects the obligations whose verification method carries evidence_kind: Fuzz, grounds each one's entry-point symbol in the repository's source, and emits targets in the repo's own harness (cargo-fuzz / atheris / fast-check) keyed on the obligation id. Writes nothing where the tooling is absent or the entry point cannot be grounded…