List the workspace credit ledger

The workspace's credit ledger, newest first: what was bought, what was spent, and what came back.

Each row carries a signed amount (negative spends, positive adds), the balanceAfter that resulted, and a stable reason code to branch on. type alone is too coarse to act on, because a refund is either a failed send returning its credit or a purchase being reversed; the reason code separates them.

Rows are redacted before they leave the process. There is no ledger row id, no user id, and no Stripe identifier: a purchase is described by its reason and its amount, and the payment behind it stays in the dashboard with the human who made it. reference is populated only when the reference is a public identifier, which today means envelopes and nothing else.

Ordering breaks ties on the underlying row id as well as the timestamp, so two entries written in the same transaction cannot swap places between two pages of the same walk.