-- The platform-wide daily AI spend ceiling sums one meter's usage across every account for a day.
CREATE INDEX usage_days_meter_day ON usage_days (meter, day);

-- When the current subscription entered past_due (NULL otherwise); the server-side grace cap counts from it.
ALTER TABLE billing_customers ADD COLUMN past_due_since INTEGER;

-- Subscriptions already past_due at deploy start their grace now rather than counting as long lapsed.
UPDATE billing_customers SET past_due_since = CAST(strftime('%s', 'now') AS INTEGER) * 1000
  WHERE subscription_status = 'past_due' AND past_due_since IS NULL;