trello.onChecklistItemDeleted matches Trello’s deleteCheckItem action.
automations/watch-trello-checklist-item-deletions.automation.ts
board as an ID, short link, or URL. Optional static account defaults to the project binding.
Returns a resource event with actionType: "deleteCheckItem", required checkItem, checklist, and board, plus actionId, occurredAt, optional card, memberCreator, and the complete provider event.