Publish As Super Node

Publish a workflow version as a reusable super node by defining its interface.

If version_number is omitted, resolves to the workflow's active_version_number. Creates (or updates) a SuperNodesModel document for this (workflow, version) pair. The workflow itself is not modified — the encapsulated workflow remains unaware of its super node status.

Captures a fully-hydrated snapshot of the workflow at publish time and stores it alongside the interface so the GET endpoint can serve it without a DB re-fetch.

Validates that:

• All NODE_CONFIG_FIELD and EDGE_CONFIG_FIELD references exist in the workflow version
• All WORKFLOW_CONFIG_FIELD paths have a valid top-level WorkflowConfig key