add computed stock bounds to gcode output

src/mode/cam/export.js

@@ -239,6 +239,7 @@
             append(`; Generated by Kiri:Moto ${KIRI.version}`);
             append(`; ${new Date().toString()}`);
             filterEmit(["; Bed left:{left} right:{right} top:{top} bottom:{bottom}"], consts);
+            append(`; Stock X:${stock.x.round(2)} Y:${stock.y.round(2)} Z:${stock.z.round(2)}`);
             append(`; Target: ${settings.filter[settings.mode]}`);
             append("; --- process ---");
             for (let pk in spro) {