Returns a flat catalog of every selectable workflow step option available to
the authenticated organization: published app creates, searches, and triggers,
plus built-in actions, triggers, and flow controls.

Each option includes input schemas and a create-ready step_template with the
keys needed to create a draft step later (via incremental step create). Dynamic
dropdown values are not included — use the workflow-apps input-options endpoint.

Access matches the workflow-apps catalog: org-owned and global published apps
only; hidden / unpublished operations are excluded.

Optional workflow_id and parent_step_id filter options to those valid at
that graph position (org-scoped; unknown IDs return 404).

OAuth callers require the workflows:read scope (and matching workspace
permission). API key callers are authorized by organization membership.