fix/123-workflow-authoring-docs
main
- Validator: hasStatusConst/getConstStatuses replace enum checks - enum in $status is now rejected with clear error message - All docs/examples/tests migrated from enum to const/oneOf - bootstrap hello.yaml updated Fixes #123
- Add type:object to all frontmatter examples (flat and oneOf) - Restructure $status section: Multi-exit (oneOf/const) vs Single-exit (flat/enum) - Add Important rules box clarifying validation requirements - Restore Custom Fields subsection Fixes #123