feat(order): add PDF export functionality and readonly order display

- Implemented PDF export feature using html2canvas and jspdf
- Added export button with loading state and disabled UI during export
- Created OrderInfoDisplay component for readonly order information
- Updated dependencies to include html2canvas and jspdf
- Modified webpack config to transpile html2canvas related packages
- Replaced OrderInfo component with OrderInfoDisplay in approval views
- Adjusted form labels and layout for better readability
- Fixed data loading state management
- Improved UI styling for PDF export mode

oms_web/oms_vue/src/views/approve/order/Approve.vue

@@ -245,9 +245,9 @@ export default {
       });
     },
     // 处理现金折扣变化
-    handleDiscountChange(value) {
+    handleDiscountChange(value, finalTotal) {
       this.selectedDiscount = value;
-      //todo 计算价格
+      this.order.actualPurchaseAmount = finalTotal;
     },
     // 处理税率变化
     handleTaxRateChange(product) {

oms_web/oms_vue/src/views/approve/order/ConfigInfo.vue

@@ -285,7 +285,7 @@ export default {
   },
   methods: {
     handleDiscountChange(value) {
-      this.$emit('discount-change', value);
+      this.$emit('discount-change', value, this.finalTotal);
     },
     handleTaxRateChange(product) {
       // 验证税率范围并限制小数位数