Create or replace a credit budget

A limit on what the org, a group, a member, a channel or an AI worker (agent) may consume per day or month. warn alerts; cap runs through the overage (default 20 %), then keeps basic chat alive and blocks heavy work until the period turns; block refuses further questions at the limit. Alerts at 70 / 80 / 90 / 100 % by default. The scope id must belong to the organization. Needs the budgets component. Audited credits.budget.put.