Customer-safe view of a subscribed workspace's spendable balance.
Plan usage is a share, never dollars. The only dollar figure is
paid_overage_usd: overage the customer explicitly bought, which only a
confirmed payment can add. It is absent, not zero, when they bought none,
so an overrun past the plan never reads as a dollar debt.
includes_given_usage says usage staff gave is part of the share, and
nothing more. It carries no amount on purpose: a top-up moves the share,
and an amount beside it would price in dollars what the customer never
bought.
status rides along because an admitted turn on a past-due account is
otherwise indistinguishable from a healthy one — the refusal payload can
only carry the warning once work is already being refused, which is after
the point of warning anyone.
spendable_now states whether the balance can be spent, rather than
leaving a client to re-derive it from the status. A balance survives the
statuses that refuse every turn, so a client deciding for itself which
those are holds a second copy of keeps_paid_access that nothing keeps
in step.