- Add safeCompare unit tests (identity, length mismatch, hex-nibble diff).
- Add Buffer-secret cases to hmac tests to lock in Svix/MS-Teams contract.
- Declare `reactflow` as a peerDependency on @sim/workflow-types — only used for type imports.
- Add a barrel export to @sim/workflow-persistence for consumers that prefer package-level imports; subpath exports retained.
- Document the data-field invariant in load.ts for loop/parallel subflow patching.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>