The account's plan state — not a site's. Response: {"status":"trialing"|"active"|"past_due"|"expired"|"trial_expired"|"none","is_trial":true,"ends_at":"RFC3339","only_hobby":false}. ends_at is when the CURRENT state stops being true (trial end while trialing, grace end — when collection stops — once trial_expired, period end otherwise) and is omitted when unknown. status "none" with only_hobby true means a free account, not a missing one. Takes no arguments.