Set Usage Price Rows

Set the cost of imported usage rows from manual per-1M rates (standalone).

Target either the current selection (ids) or everything matching a filter (by_filter: true). Cost / billing meters / pricing breakdown are recomputed from each row's own token counts at the supplied input / output / cache_read / cache_write per-1M rates (manual rates, not a recompute from configured pricing). Only imported rows (counts_toward_budget = false) are touched, so users.spend is never affected. Master-key only.