Fix workflow-types provenance metadata

[khaliqgant]

Summary

• add repository metadata to @agent-relay/workflow-types so npm provenance validation sees the GitHub repository instead of an empty repository URL
• verified the packed tarball includes the repository object

Verification

• publishable package repository metadata scan
• npm pack --ignore-scripts for packages/workflow-types and inspected package/package.json from the tarball
• git diff --check origin/main...HEAD