feat: 支持同卡种续卡叠加并修复过期登录态

支付成功后将次数或有效期叠加到已有会员卡，首页与详情页引导续卡；接口 401 时同步清掉本地登录态。

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/shared/src/index.ts

@@ -30,6 +30,27 @@ export {
   SUBSCRIPTION_MESSAGE_REQUEST_RESULTS,
 } from './constants'
 
+export {
+  RENEWAL_TIMES_THRESHOLD,
+  RENEWAL_DAYS_THRESHOLD,
+  MEMBERSHIP_DAY_MS,
+  addDurationDays,
+  getMembershipDaysLeft,
+  canRenewCardType,
+  computeMembershipGrant,
+  pickRenewalTarget,
+  getMembershipRenewalHint,
+} from './membership-renewal'
+
+export type {
+  MembershipGrantExisting,
+  MembershipGrantCardType,
+  MembershipGrantResult,
+  MembershipRenewalHintKind,
+  MembershipRenewalHint,
+  RenewalHintMembership,
+} from './membership-renewal'
+
 // Types
 export type {
   User,