Summary

• expand external example READMEs with SPEC-0019-style user job, dependency, import, positive path, negative path, and boundary sections
• split the rust-test-fixtures example into a positive RSA/JWK facade path and a negative API-key near-miss parser path
• reword the downstream CI audit example boundary away from scanner-evasion language
• advance the usability-polish goal from facade examples to external library smoke

Boundaries

• no release prep, version bump, tag, or publish
• no new contract packs, badges, provider compatibility claims, production security claims, or broad facade redesign
• no installed CLI execution of xtask or claim-ledger commands

Validation

• cargo fmt --all -- --check
• cargo test --manifest-path examples/external/rust-test-fixtures/Cargo.toml
• cargo test -p xtask external_adoption_smoke
• cargo +nightly xtask external-adoption-smoke --path .
• cargo +nightly xtask docs-sync --check
• cargo +nightly xtask typos
• cargo +nightly xtask pr-lite
• git diff --check
• scanner-evasion wording search returned no matches in the edited examples and active goal

Note: the generated external example Cargo.lock was removed before final validation and is not committed.