feat(crm/contract): 优化合同产品材质输入与导出样式

1. 将材质输入框改为可搜索创建的选择器，新增冷轧卷(花纹)选项和SPCC等材质选项
2. 优化合同导出表格的边框、内边距和字体样式，统一表格样式

klp-ui/src/views/crm/contract/components/ProductContent.vue

@@ -50,7 +50,9 @@
           <el-input v-model="item.spec" placeholder="请输入规格" :readonly="readonly" size="small" />
         </div>
         <div class="table-cell">
-          <el-input v-model="item.material" placeholder="请输入材质" :readonly="readonly" size="small" />
+          <el-select v-model="item.material" placeholder="请选择材质" :readonly="readonly" size="small" filterable allow-create clearable style="width:100%;">
+            <el-option v-for="opt in materialOptions" :key="opt.value" :label="opt.label" :value="opt.value" />
+          </el-select>
         </div>
         <div class="table-cell">
           <el-input v-model="item.quantity" placeholder="请输入数量" :readonly="readonly" size="small"
@@ -149,7 +151,13 @@ export default {
         { label: '冷硬钢卷', value: '冷硬钢卷' },
         { label: '镀锌钢卷', value: '镀锌钢卷' },
         { label: '冷轧钢卷', value: '冷轧钢卷' },
+        { label: '冷轧卷(花纹)', value: '冷轧卷(花纹)' },
         { label: '镀铬钢卷', value: '镀铬钢卷' },
+      ],
+      materialOptions: [
+        { label: 'SPCC', value: 'SPCC' },
+        { label: 'BX51D+Z', value: 'BX51D+Z' },
+        { label: 'DC01', value: 'DC01' },
       ]
     }
   },