refactor: 统一全项目金额精度为角（0.1元）

## 变更概述
将全项目金额处理从整元四舍五入统一为角精度（0.1元），提高金额计算准确性和显示一致性。

## 后端改动
- 新增 pkg/money/format.go 统一金额处理包
  - Round(): 角精度四舍五入
  - Min/Max(): 金额比较
  - Format(): 格式化字符串
- 更新业务模块使用统一金额函数
  - internal/modules/order: 订单结算改为角精度
  - internal/modules/dispute: 纠纷金额处理
  - internal/modules/listing: 商品定价和存储
- 更新测试用例期望值为角精度

## 前端改动
- 新增 shared/utils/money.ts 金额工具函数
  - roundMoney(): 角精度四舍五入
  - formatMoney(): 格式化为字符串（保留1位小数）
  - formatMoneyWithSymbol(): 添加¥符号
- 更新金额计算和显示逻辑
  - shared/utils/pricing.ts: 定价计算
  - shared/utils/listingDisplay.ts: 商品显示
  - shared/composables/useMoney.ts: 组合式函数
- 修复视图文件导入声明
  - features/listings/views: 商品详情页
  - features/seller/views: 卖家管理页

## 效果
- 金额显示：¥123.0（统一保留1位小数）
- 计算精度：12.45 -> 12.5（角精度）
- 减少误差：避免整元四舍五入损失
- 显示一致：全项目统一格式

## 测试
- ✅ 后端单元测试通过
- ✅ TypeScript 类型检查通过
- ✅ 开发环境正常运行

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/features/listings/views/ListingDetailView.vue

@@ -6,6 +6,7 @@ import { useRoute, useRouter } from "vue-router";
 import { fetchListing, type Listing } from "@/features/listings/api/listings";
 import { createOrder } from "@/features/orders/api/orders";
 import { useSessionStore } from "@/stores/session";
+import { roundMoney, formatMoney } from "@/shared/utils/money";
 import {
   assetRegions,
   formatEstimatedRentalDuration,
@@ -45,7 +46,7 @@ onMounted(async () => {
 
 const orderTotal = computed(() => {
   if (!listing.value) return "0";
-  return `${Math.round(getListingDisplayPrice(listing.value))}`;
+  return formatMoney(getListingDisplayPrice(listing.value));
 });
 
 const orderPriceBreakdown = computed(() => {
@@ -59,7 +60,7 @@ const orderPriceBreakdown = computed(() => {
   return {
     rent: getListingRentPrice(listing.value),
     consumable: getListingConsumablePrice(listing.value),
-    total: Math.round(getListingDisplayPrice(listing.value)),
+    total: roundMoney(getListingDisplayPrice(listing.value)),
   };
 });
 
@@ -158,7 +159,7 @@ function readError(error: unknown, fallback: string) {
 }
 
 function listingPrice(item: Listing) {
-  return `${Math.round(getListingDisplayPrice(item))}`;
+  return formatMoney(getListingDisplayPrice(item));
 }
 </script>
 

frontend/src/features/listings/views/MobileListingDetailView.vue

@@ -6,6 +6,7 @@ import { showToast, showDialog } from "vant";
 import { fetchListing, type Listing } from "@/features/listings/api/listings";
 import { createOrder } from "@/features/orders/api/orders";
 import { useSessionStore } from "@/stores/session";
+import { formatMoney } from "@/shared/utils/money";
 import {
   assetRegions,
   formatHafCoinM,
@@ -43,8 +44,8 @@ onMounted(async () => {
 });
 
 const orderTotal = computed(() => {
-  if (!listing.value) return "0";
-  return `${Math.round(getListingDisplayPrice(listing.value))}`;
+  if (!listing.value) return "0.0";
+  return formatMoney(getListingDisplayPrice(listing.value));
 });
 
 const orderPriceBreakdown = computed(() => {