Tasks — crypto-utils-spec-conformance

Add **Verified by:** line to every ### Requirement: block in openspec/specs/crypto-utils/spec.md.
Add src/no-vendored.spec-conformance.test.ts pinning the "no vendored directory" scenario.
Confirm bun scripts/openspec-conformance.ts @suaveplan/crypto-utils exits 0.
Confirm bunx turbo lint typecheck test --filter=@suaveplan/crypto-utils is green.
Confirm bunx turbo test:coverage --filter=@suaveplan/crypto-utils reports 100/100/100/100.