Retrieve usage

Retrieve your workspace's current billing-period usage snapshot: the plan, the period window, and the email counter. On paid plans the response also carries the dollar sending wallet: the monthly allowance included with the plan, spend so far, any upgrade carryover, the non-expiring purchased-credit balance, and billable overage, all as integer USD cents. On the free plan wallet is null and the emails object carries the monthly quota and daily cap instead. spend itemizes the period from the wallet ledger (email, SMS, SMS carrier fees, refunds, and how it was paid), and sms breaks SMS down by destination country with segments, the price per segment, monthly number and campaign fees, one-time registration fees, and refunds. Amounts are read from the same ledger and meters that gate sending, so this matches the dashboard statement exactly. Requires the emails:read or sms:read capability.