Approximate platform counters, with the rate they move at

Two numbers and their speed: checks.value is addresses screened, attributions.value is addresses we hold a name for, and each carries per_second.

The screening total is counted; the attribution total is a planner estimate, which is what approximate: true means: it is right to within a rounding, not to the row. The rate is there so a caller can animate the number locally instead of polling us for it. Re-poll no more often than refresh_after_seconds; a faster poll returns the same cached answer with cached: true.

The screening total counts requests we have logs for, so it starts at the day request logging was switched on, plus an operator-set baseline where one is configured. Our own machinery is not in it: the website's server-side rendering of its address pages and our news conveyor are logged but not counted, so the number is addresses somebody asked about and not work we scheduled ourselves.