trello.listCardCustomFieldValues lists every populated Custom Field value on one card.
automations/list-trello-card-custom-field-values.automation.ts
card as an ID, short link, or standard card URL. Optional second argument { account } selects a Trello binding.
Returns Signal<TrelloCustomFieldItem[]>. Each item includes id, cardId, customFieldId, and a value discriminated by type: checkbox checked, date date, list optionId, number number, or text text.