Publish Harbor Saved Query Draft

Validates and publishes the current draft as the next immutable saved-query version. Only organization administrators can publish. Publication executes and validates the current draft with the Polytomic-managed Harbor's MotherDuck `read_scaling` credential. It fails instead of using the Harbor writer credential when the reader credential is missing or incomplete. After execution, publication verifies that the draft did not change. A concurrent edit returns a conflict and remains a draft. Successful publication creates the next immutable revision, records the observed ordered columns as its output contract, removes validation inputs from the published definition, and deletes the mutable draft. The response includes the immutable `revision_id` that future executions use for exact provenance.