refactor: replace border-box with box-border and clean up unused scss

Remove the unused box-sizing.scss stylesheet and its import from the main SCSS index file.
Update all Vue component template class references from the custom border-box class to the
native box-border utility class to eliminate redundant custom CSS and align with the project's
utility class conventions.

src/pages-service/order/components/OrderCard/index.vue

@@ -1,5 +1,5 @@
 <template>
-  <view class="order-card bg-white border-box p-[12px] rounded-12 m-12">
+  <view class="order-card bg-white box-border p-[12px] rounded-12 m-12">
     <!-- 卡片头部 -->
     <view class="border-box flex flex-items-center pb-[12px]">
       <image class="icon mr-4" src="https://oss.nianxx.cn/mp/static/version_101/service/service_icon.png" />
@@ -21,7 +21,7 @@
 
     <!-- 服务人员 -->
     <view v-if="orderData.processMemberName && orderData.processMemberPhone"
-      class="service-user border-box p-[8px] flex flex-items-center flex-justify-between mb-12">
+      class="service-user box-border p-[8px] flex flex-items-center flex-justify-between mb-12">
       <view class="font-size-12 line-height-16">服务人员：{{ orderData.processMemberName }}</view>
       <uni-icons class="ml-auto mr-4" type="phone-filled" size="14" color="#436799" />
       <text class="font-size-12 line-height-16" @click="callService">拨打电话</text>
@@ -33,7 +33,7 @@
       orderData.workOrderStatus !== '2' &&
       orderData.workOrderStatus !== '3'
     " class="flex flex-items-center flex-justify-between">
-      <text class="cancel border-box border rounded-6 font-size-12 line-height-16 color-525866 ml-auto"
+      <text class="cancel box-border border rounded-6 font-size-12 line-height-16 color-525866 ml-auto"
         @click="cancelCall">取消呼叫</text>
     </view>
   </view>