Fix Bug #517: [库房管理-领用管理] 业务逻辑校验缺失：允许保存并提交领用数量大于库存数量（零库存领用）的单据

根因分析：
- 前端 handleSubmitApproval（提交审批）未做库存校验，直接调用后端 API
- 后端 submitApproval 也未做库存校验，仅在保存时（addOrEditIssueReceipt）有 validateRequisitionStock
- 用户可绕过前端保存校验（如编辑已有草稿后直接提交审批），将超库存单据提交审批流

修复方案：
1. 后端：在 submitApproval 方法中增加 validateRequisitionStockByBusNo，通过单据详情查询已保存明细，逐行校验领用数量是否超过源仓库库存
2. 前端：在 handleSubmitApproval 提交前逐行调用 validateRequisitionQtyVsStock 校验库存，超库存时拦截并提示

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

openhis-ui-vue3/src/views/medicationmanagement/requisitionManagement/requisitionManagement/index.vue

@@ -982,6 +982,16 @@ function handleSubmitApproval() {
   } else if (!form.purchaseinventoryList[length - 1].isSave) {
     proxy.$modal.msgWarning('第' + length + '行单据未保存，请先保存');
   } else {
+    // 提交审批前逐行校验库存，防止超库存单据进入审批
+    for (let i = 0; i < form.purchaseinventoryList.length; i++) {
+      const line = form.purchaseinventoryList[i];
+      if (!line) continue;
+      const err = validateRequisitionQtyVsStock(line, i + 1);
+      if (err) {
+        proxy.$modal.msgWarning(err);
+        return;
+      }
+    }
     submitApproval(receiptHeaderForm.busNo).then((response) => {
       if (response.code == 200) {
         proxy.$modal.msgSuccess('提交审批成功');