feat(checkout): 修复后置损耗结算全额归号主、支持角色隔离实时试算与全流程UI重构

- fix(pricing): 后置消耗/损耗金额 100% 划归号主收益，超出预收部分平台不抽成，避免被平台费吸收
- feat(checkout): 前端新增结账实时试算预览组件 (CheckoutTrialPreview + useCheckoutSimulator)，角色隔离展示（仅见自身收入/退款，屏蔽平台服务费）
- refactor(admin): 重构交易全流程时间线 (ProcessTimeline.vue)，将平铺挤压指标重构成4大分类仪表盘微型卡片矩阵，升级可视化业务状态流转徽章与阶段色彩主题
- style(admin): 优化支付与交接流水元信息网格布局，防止超宽屏下长单行拉伸

frontend/src/features/orders/views/MobileOrderDetailView.vue

@@ -5,6 +5,8 @@ import { showDialog, showToast } from 'vant'
 
 import MobilePaymentCashierPopup from '@/features/orders/components/MobilePaymentCashierPopup.vue'
 import MobilePayWaySelectPopup from '@/features/orders/components/MobilePayWaySelectPopup.vue'
+import CheckoutTrialPreview from '@/features/orders/components/CheckoutTrialPreview.vue'
+import { useCheckoutSimulator } from '@/features/orders/composables/useCheckoutSimulator'
 import { useOrderActions, CONFIRMABLE_ACTIONS } from '@/features/orders/composables/useOrderActions'
 import { useMobilePaymentCashier } from '@/features/orders/composables/useMobilePaymentCashier'
 import { useMobilePayWaySelect } from '@/features/orders/composables/useMobilePayWaySelect'
@@ -129,6 +131,13 @@ const showCheckoutCounterAction = computed(
       (isRenter.value && order.value.status === 'pending_checkout_accept'))
 )
 
+const checkoutSimulation = useCheckoutSimulator({
+  order,
+  isOwner,
+  isRenter,
+  form: counterForm,
+})
+
 // 状态颜色映射（vant 标签主题）。
 function getStatusTagType(status: string) {
   if (['completed', 'received'].includes(status)) return 'success'
@@ -505,7 +514,7 @@ async function copyListingCode() {
           }}。可填实际哈夫币消耗（允许超过发布量），打超按比例从押金扣。提案将交给对方确认。
         </p>
         <van-cell-group :border="false">
-          <van-field label="额外消耗品已用">
+          <van-field label="物资/损耗金额">
             <template #input>
               <input
                 v-model.number="counterForm.consumableAmountYuan"
@@ -533,6 +542,9 @@ async function copyListingCode() {
             </template>
           </van-field>
         </van-cell-group>
+
+        <!-- 实时结算试算预览（仅展示当前角色自身收支，完全屏蔽平台服务费） -->
+        <CheckoutTrialPreview :simulation="checkoutSimulation" variant="mobile" />
         <van-field
           v-model="counterForm.reason"
           rows="2"