Delete a knowledge item

Permanently remove a knowledge item from a Mind together with its thinking patterns, its retrieval embeddings, and (for uploads) the stored file. The item record is deleted last; if a dependent cleanup step fails it is logged and the deletion still succeeds, so a 204 means the item is gone from the Mind and will no longer be retrieved in chat. This cannot be undone. The Mind system prompt is not regenerated by this call. Access: you must be able to edit the Mind (owner, direct collaborator, or member of the team the Mind is shared with); other Minds answer 404 Mind not found or access denied.