aiBuildStructureFromSource
ONE-SHOT server-side import: deterministically reconstruct the email's V46 layout from a source (pasted HTML or a URL), create the email (same CreateEmail path as the dialog's other flows), and run the AI refinement — when corrections land, the refined tree becomes the live revision and the deterministic build stays as a soft-deleted audit revision (the same two-revision trail ai:build-structure keeps). Returns the created email; the frontend just redirects into the builder. Alpha: gated to internal + Merlin Leonard products (see InternalProductIds::AI_STRUCTURE_IMPORT_PIDS).
aiBuildStructureFromSource(
input: AiBuildStructureFromSourceInput!
): NextGenEmail!
