Interface SlaWindow

SLA window expressed as a structured duration. Mirrors sla-window.json as a { unit, value } pair (e.g. { unit: 'hours', value: 24 }). The schema landed alongside #4514 but is intentionally minimal; the spec calls out that absence means "no commitment", not "zero commitment".

interface SlaWindow {
    unit: "minutes" | "hours" | "days" | "business_days";
    value: number;
    response_max?: number;
}