feat: 下线支付功能； 月卡生效时间从第一次约课开始

packages/server/prisma/migrations/20261030090000_monthly_first_check_in/migration.sql

@@ -0,0 +1,5 @@
+-- Preserve all historical periods. New monthly cards have no dates until first check-in.
+ALTER TABLE `memberships`
+  MODIFY `start_date` DATETIME(3) NULL,
+  MODIFY `expire_date` DATETIME(3) NULL,
+  ADD COLUMN `activation_duration_days` INTEGER NULL;

packages/server/prisma/schema.prisma

@@ -163,8 +163,9 @@ model Membership {
   cardTypeId     String           @map("card_type_id")
   remainingTimes Int?             @map("remaining_times")
   totalTimes     Int?             @map("total_times")
-  startDate      DateTime         @map("start_date")
-  expireDate     DateTime         @map("expire_date")
+  startDate      DateTime?        @map("start_date")
+  expireDate     DateTime?        @map("expire_date")
+  activationDurationDays Int?     @map("activation_duration_days")
   status         MembershipStatus @default(ACTIVE)
   createdAt      DateTime         @default(now()) @map("created_at")
   updatedAt      DateTime         @updatedAt @map("updated_at")