feat(task1): restructure directories for turborepo monorepo

- Move backend/ to apps/server/ via git mv
- Move frontend/ to apps/admin/ via git mv
- Create packages/typescript-config/ with base, nestjs, and react-vite presets

apps/server/src/entities/index.ts

@@ -0,0 +1,15 @@
+export { Student } from './student.entity';
+export { Room } from './room.entity';
+export { Occupancy } from './occupancy.entity';
+export { RoomExpense } from './room-expense.entity';
+export { PersonalExpense } from './personal-expense.entity';
+export { Bill } from './bill.entity';
+export { BillItem } from './bill-item.entity';
+export { User } from './user.entity';
+export { OperationLog } from './operation-log.entity';
+export { Deposit } from './deposit.entity';
+export { Classroom } from './classroom.entity';
+export { Tenant } from './tenant.entity';
+export { ClassroomRental } from './classroom-rental.entity';
+export { Permission } from './permission.entity';
+export { Role } from './role.entity';