feat(paid-member): 添加付费会员功能模块

- 新增付费会员API接口层，支持会员查询、下单、记录及报价
- 新增付费会员页面，展示权益、推荐商品及购买流程
- 新增付费会员购买记录页面，支持订单状态查看与继续支付
- 新增 PaidMemberPrice 组件用于商品列表和详情页展示会员价
- 个人中心页添加付费会员入口，支持配置化展示标题与背景
- 商品详情页集成会员价展示，支持秒杀和拼团场景下隐藏
- 商品列表组件集成会员价展示，支持批量请求与防竞态
- 支付页适配付费会员支付流程，支持H5轮询与结果回调
- 订单确认页优惠文案更新为"活动优惠（含会员优惠）"
- pages.json 新增付费会员及购买记录页面路由配置
- README 更新升级计划，按时间倒序补充已完成功能明细

api/paid-member.js

@@ -0,0 +1,7 @@
+import { http, Method } from '@/utils/request.js'
+export const getPaidMember = () => http.request({ url: '/member/paid/current', method: Method.GET, needToken: true })
+export const createPaidMemberOrder = data => http.request({ url: '/member/paid/orders', method: Method.POST, data, needToken: true, header: { 'Content-Type': 'application/json' } })
+export const getPaidMemberOrders = params => http.request({ url: '/member/paid/orders', method: Method.GET, params, needToken: true })
+export const getPaidMemberOrder = sn => http.request({ url: `/member/paid/orders/${encodeURIComponent(sn)}`, method: Method.GET, needToken: true })
+export const cancelPaidMemberOrder = sn => http.request({ url: `/member/paid/orders/${encodeURIComponent(sn)}/cancel`, method: Method.POST, needToken: true })
+export const getPaidMemberQuotes = skuIds => http.request({ url: '/member/paid/quotes', method: Method.GET, params: { skuIds: skuIds.join(',') }, needToken: true })