Convert deprecated PromotedOfferings to the new Catalog type.
Inline offerings map to a Catalog with type 'offering' and items populated from offerings[].
Note: si_agent_url, product_selectors, and asset_selectors are not preserved in the
Catalog type — callers must migrate these fields separately.
Convert deprecated PromotedOfferings to the new Catalog type. Inline offerings map to a Catalog with type 'offering' and items populated from offerings[].
Note: si_agent_url, product_selectors, and asset_selectors are not preserved in the Catalog type — callers must migrate these fields separately.