feat(server): add membership and time-slot modules

Membership: card type CRUD, deduction/restore logic, valid card lookup (15 tests)
TimeSlot: slot generation from week templates, availability query with booking
status, admin management, cleanup tasks (26 tests)
65 total tests passing

packages/server/src/time-slot/time-slot.module.ts

@@ -0,0 +1,11 @@
+import { Module } from '@nestjs/common'
+import { TimeSlotController, AdminTimeSlotController } from './time-slot.controller'
+import { TimeSlotService } from './time-slot.service'
+import { SlotGeneratorService } from './slot-generator.service'
+
+@Module({
+  controllers: [TimeSlotController, AdminTimeSlotController],
+  providers: [TimeSlotService, SlotGeneratorService],
+  exports: [TimeSlotService, SlotGeneratorService],
+})
+export class TimeSlotModule {}