Type Alias PinnedUsageSnapshot

A rolling-window usage snapshot as pinned into productQuoteTable.aggregateUsage. Mirrors the service-layer UsageSnapshot field for field, with every figure rendered as a decimal string — BigNumber doesn't round-trip through JSON.parse, the same reason ProductQuoteData and PinnedLimitViolation store their numerics as strings. Key order matches UsageSnapshot's (calendar-month last); treat it as append-only.