List Catalog Items
Lists catalog items for the authenticated merchant, including current HSA/FSA eligibility for each item.
This endpoint is intended to complement the `Item Eligibility Updated` webhook: use the webhook to receive ongoing updates, and use this endpoint to enumerate items that were already categorized before webhook ingestion began (or to reconcile after a gap).
Use `eligibility` to scope the response to a specific eligibility state, and `updated_after` to incrementally sync only items changed since the last poll.