Restore public OpenAPI security metadata

[muxx]

Summary

• restore only normalized public API-key schemes in generated OpenAPI reference files
• emit operation-level security from the neutral operations.json auth contract
• verify every published operation and scheme in the reference contract test

Checks

• make generate
• pnpm format:check
• pnpm lint
• pnpm typecheck
• pnpm test
• pnpm check:public
• pnpm test:release
• pnpm check:generated