D3 first half: x_fc_workorder_count computes live count of active MRP work orders linked to this SO (via mo.origin = so.name). Adds a 'Active WOs' smart button next to the existing PO / RFQ buttons on the sale.order form. Clicking opens a filtered mrp.workorder list grouped by MO. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>