refactor: 常量化订单状态 + 支付渠道/提供商分离显示 + H5自动跳转

- 新增 src/lib/constants.ts，集中管理 ORDER_STATUS / PAYMENT_TYPE / PAYMENT_PREFIX 等常量
- 后端 service/status/timeout/limits 全量替换魔法字符串为 ORDER_STATUS.*
- PaymentTypeMeta 新增 provider 字段，分离 sublabel（选择器展示）与 provider（提供商名称）
- getPaymentDisplayInfo() 返回 { channel, provider } 用于用户端/管理端展示
- 支持通过 PAYMENT_SUBLABEL_* 环境变量覆盖默认 sublabel
- PaymentQRCode: H5 支付自动跳转（含易支付微信 weixin:// scheme 兜底）
- 订单列表/详情页：显示可读的渠道名+提供商，不再暴露内部标识符

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/lib/constants.ts

@@ -0,0 +1,51 @@
+/** 订单状态 */
+export const ORDER_STATUS = {
+  PENDING: 'PENDING',
+  PAID: 'PAID',
+  RECHARGING: 'RECHARGING',
+  COMPLETED: 'COMPLETED',
+  EXPIRED: 'EXPIRED',
+  CANCELLED: 'CANCELLED',
+  FAILED: 'FAILED',
+  REFUNDING: 'REFUNDING',
+  REFUNDED: 'REFUNDED',
+  REFUND_FAILED: 'REFUND_FAILED',
+} as const;
+
+export type OrderStatus = (typeof ORDER_STATUS)[keyof typeof ORDER_STATUS];
+
+/** 终态状态集合（不再轮询） */
+export const TERMINAL_STATUSES = new Set<string>([
+  ORDER_STATUS.COMPLETED,
+  ORDER_STATUS.FAILED,
+  ORDER_STATUS.CANCELLED,
+  ORDER_STATUS.EXPIRED,
+  ORDER_STATUS.REFUNDED,
+  ORDER_STATUS.REFUND_FAILED,
+]);
+
+/** 退款相关状态 */
+export const REFUND_STATUSES = new Set<string>([
+  ORDER_STATUS.REFUNDING,
+  ORDER_STATUS.REFUNDED,
+  ORDER_STATUS.REFUND_FAILED,
+]);
+
+/** 支付方式标识 */
+export const PAYMENT_TYPE = {
+  ALIPAY: 'alipay',
+  ALIPAY_DIRECT: 'alipay_direct',
+  WXPAY: 'wxpay',
+  WXPAY_DIRECT: 'wxpay_direct',
+  STRIPE: 'stripe',
+} as const;
+
+/** 支付方式前缀（用于 startsWith 判断） */
+export const PAYMENT_PREFIX = {
+  ALIPAY: 'alipay',
+  WXPAY: 'wxpay',
+  STRIPE: 'stripe',
+} as const;
+
+/** 需要页面跳转（而非二维码）的支付方式 */
+export const REDIRECT_PAYMENT_TYPES = new Set<string>([PAYMENT_TYPE.ALIPAY_DIRECT]);