feat(idempotency): 为关键写接口接入幂等并完善并发容错

backend/cmd/server/wire.go

@@ -74,6 +74,7 @@ func provideCleanup(
 	accountExpiry *service.AccountExpiryService,
 	subscriptionExpiry *service.SubscriptionExpiryService,
 	usageCleanup *service.UsageCleanupService,
+	idempotencyCleanup *service.IdempotencyCleanupService,
 	pricing *service.PricingService,
 	emailQueue *service.EmailQueueService,
 	billingCache *service.BillingCacheService,
@@ -147,6 +148,12 @@ func provideCleanup(
 				}
 				return nil
 			}},
+			{"IdempotencyCleanupService", func() error {
+				if idempotencyCleanup != nil {
+					idempotencyCleanup.Stop()
+				}
+				return nil
+			}},
 			{"TokenRefreshService", func() error {
 				tokenRefresh.Stop()
 				return nil