CNC执行 → PipelineExecutionService(返回 LastStepOutputData) → CncExecutionService(调用 PushDetectionOverlay) → MainViewportService(触发 DetectionOverlayUpdated 事件) → ViewportPanelView(订阅事件,调用 DetectionOverlayRenderer) → PolygonRoiCanvas.SetDetectionOverlayCanvas(插入叠加层 Canvas)