Get Work Order Summary

Operates on Service Orders, shown in the Zuper client app as "Work Order" (in every industry). Work Orders share the exact same underlying schema and endpoints as Purchase Orders / Material Orders; they're distinguished only by the purchase_order_type field (SERVICE_ORDER here) and the /service_orders route prefix. Returns order counts/totals overall and broken down by status, plus an OVERDUE bucket (orders past their due_date in an active pre-fulfillment status).