Class InMemorySubscriptionStore

Optional scale path for chargeDueSubscriptions: return records that are due — active/trialing with currentPeriodEnd <= dueBefore, or past_due with nextRetryAt <= dueBefore — never canceled or paused ones, in a stable order, at most limit of them. Push the predicate into a database index; the manager pages until a short batch and still re-checks due-ness per record, so this filter is an optimization, not a trust boundary. Without it the manager falls back to per-status list() scans.