feat: P1阶段完成 - 订单模块迁移与重构

## P1.3: 订单模块（orders）✅

### 完整迁移
- 迁移 API: orders.ts
- 迁移 Views: 5个页面（桌面3 + 移动2）
- 迁移 Composables: useOrderSnapshot.ts
- 更新所有导入路径到 shared/

### 核心重构：拆分 useOrderDetail.ts
原始文件405行，混合了订单、支付、结算、争议等多个领域

**拆分为3个独立 composables：**

1. **usePaymentPolling.ts** - 支付轮询
   - 职责：轮询查询支付状态直到完成
   - 功能：开始/停止轮询、检查支付状态、自动重载
   - 代码：~65行

2. **useSettlement.ts** - 结算流程
   - 职责：处理订单结算完整流程
   - 功能：提交/接受/反驳/确认结算、表单管理
   - 代码：~170行

3. **useOrderDetail.ts** - 核心订单（重构后）
   - 职责：订单核心流程，组合使用上述composables
   - 功能：加载、取消、支付、交接、收货、争议
   - 代码：~215行

**重构优势：**
- 职责清晰，单一职责原则
- 可复用，支付和结算逻辑可独立使用
- 易测试，每个composable独立可测
- 易维护，从405行拆分为3个文件

### 技术改进
- 建立清晰的模块边界和导出规范
- 避免循环依赖
- 提高代码可测试性和可维护性

## 里程碑

🎉 **P1 阶段完成！**

- ✅ P0: 基础设施（shared/）- 22个文件
- ✅ P1.1: 钱包模块 - 5个文件
- ✅ P1.2: 聊天模块 - 8个文件
- ✅ P1.3: 订单模块 - 11个文件

**总计：** 3个核心业务模块，46个文件完成迁移

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

frontend/src/features/orders/composables/useOrderSnapshot.ts

@@ -0,0 +1,147 @@
+import type { Order } from '../api/orders'
+
+export interface SnapshotResource {
+  key: string
+  label: string
+  quantity: number
+  unitPrice: number
+  chargeMode: '赠送' | '收费'
+}
+
+export function readSnapshot(order: Order | null) {
+  if (!order?.listing_snapshot) return null
+  try {
+    return JSON.parse(order.listing_snapshot) as Record<string, any>
+  } catch {
+    return null
+  }
+}
+
+export function readNumber(value: unknown): number {
+  const parsed = Number(value)
+  return Number.isFinite(parsed) ? parsed : 0
+}
+
+export function roundQuantity(value: number): number {
+  return Math.round(value * 10) / 10
+}
+
+export function roundMoney(value: number): number {
+  return Math.round(value * 100) / 100
+}
+
+export function readSnapshotResources(order: Order | null): SnapshotResource[] {
+  const snapshot = readSnapshot(order)
+  if (!snapshot?.quantities) return []
+
+  const quantities = snapshot.quantities as Record<string, any>[]
+  return quantities
+    .map((item) => ({
+      key: String(item.key || ''),
+      label: String(item.label || ''),
+      quantity: readNumber(item.quantity),
+      unitPrice: readNumber(item.price),
+      chargeMode: item.charge_mode === '收费' ? '收费' : '赠送',
+    }))
+    .filter((item) => item.key && item.label)
+}
+
+export function isChargedResource(resource: SnapshotResource): boolean {
+  return resource.chargeMode === '收费'
+}
+
+export function getSnapshotHafCoinM(order: Order | null): number {
+  const snapshot = readSnapshot(order)
+  return roundQuantity(readNumber(snapshot?.haf_coin_amount) / 1000000)
+}
+
+export function calculateResourceChargeAmount(
+  resources: SnapshotResource[],
+  resourceUsage: Record<string, number>
+): number {
+  return roundMoney(
+    resources.reduce((sum, item) => {
+      if (!isChargedResource(item)) return sum
+      const used = resourceUsage[item.key] || 0
+      return sum + used * item.unitPrice
+    }, 0)
+  )
+}
+
+export function calculateCheckoutTotal(
+  resourceCharge: number,
+  consumableAmount: number,
+  coinConsumed: number,
+  otherAmount: number
+): number {
+  return roundMoney(resourceCharge + consumableAmount + coinConsumed + otherAmount)
+}
+
+export function calculateCounterTotal(counterForm: {
+  consumable_amount: number
+  coin_consumed_m: number
+  other_amount: number
+  deposit_deduct_amount: number
+}): number {
+  return roundMoney(
+    counterForm.consumable_amount +
+      counterForm.coin_consumed_m +
+      counterForm.other_amount +
+      counterForm.deposit_deduct_amount
+  )
+}
+
+export function hydrateResourceUsageFromOrder(
+  order: Order | null,
+  resources: SnapshotResource[]
+): Record<string, number> {
+  const usage: Record<string, number> = {}
+
+  if (!order?.checkout_info) {
+    return usage
+  }
+
+  try {
+    const info = JSON.parse(order.checkout_info) as Record<string, any>
+    const consumedResources = info.consumed_resources as Record<string, number> | undefined
+
+    if (consumedResources) {
+      resources.forEach((res) => {
+        if (res.key in consumedResources) {
+          usage[res.key] = consumedResources[res.key]
+        }
+      })
+    }
+  } catch {
+    // ignore
+  }
+
+  return usage
+}
+
+export function hydrateCounterFormFromOrder(order: Order | null) {
+  if (!order?.counter_info) {
+    return null
+  }
+
+  try {
+    const info = JSON.parse(order.counter_info) as Record<string, any>
+    return {
+      consumable_amount: readNumber(info.consumable_amount),
+      coin_consumed_m: readNumber(info.coin_consumed_m),
+      other_amount: readNumber(info.other_amount),
+      deposit_deduct_amount: readNumber(info.deposit_deduct_amount),
+      reason: String(info.reason || ''),
+      evidenceText: String(info.evidence || ''),
+    }
+  } catch {
+    return null
+  }
+}
+
+export function readError(error: unknown, fallback: string): string {
+  if (error && typeof error === 'object' && 'message' in error) {
+    return String(error.message)
+  }
+  return fallback
+}