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/deposits/deposits.service.ts

@@ -0,0 +1,66 @@
+import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository } from 'typeorm';
+import { Deposit } from '../entities/deposit.entity';
+import { CreateDepositDto, RefundDepositDto } from './dto/deposit.dto';
+
+@Injectable()
+export class DepositsService {
+  constructor(@InjectRepository(Deposit) private repo: Repository<Deposit>) {}
+
+  async findAll(query?: { studentId?: number; status?: string }) {
+    const qb = this.repo.createQueryBuilder('d')
+      .leftJoinAndSelect('d.student', 'student')
+      .orderBy('d.createdAt', 'DESC');
+    if (query?.studentId) qb.andWhere('d.studentId = :studentId', { studentId: query.studentId });
+    if (query?.status) qb.andWhere('d.status = :status', { status: query.status });
+    return qb.getMany();
+  }
+
+  async create(dto: CreateDepositDto, userId?: number) {
+    return this.repo.save(this.repo.create({
+      studentId: dto.studentId,
+      amount: dto.amount,
+      paidDate: dto.paidDate,
+      notes: dto.notes,
+      status: 'paid',
+      recordedBy: userId,
+    }));
+  }
+
+  async refund(id: number, dto: RefundDepositDto, userId?: number) {
+    const deposit = await this.repo.findOne({ where: { id } });
+    if (!deposit) throw new NotFoundException('押金记录不存在');
+    if (deposit.status !== 'paid') throw new BadRequestException('该押金已处理');
+
+    const deduction = dto.deductionAmount || 0;
+    const refundAmount = Number(deposit.amount) - deduction;
+    if (refundAmount < 0) throw new BadRequestException('扣除金额不能大于押金金额');
+
+    deposit.refundDate = dto.refundDate;
+    deposit.deductionAmount = deduction;
+    deposit.deductionReason = dto.deductionReason || '';
+    deposit.refundAmount = refundAmount;
+    deposit.status = deduction > 0 ? (refundAmount > 0 ? 'partial_refund' : 'deducted') : 'refunded';
+    if (dto.notes) deposit.notes = dto.notes;
+
+    return this.repo.save(deposit);
+  }
+
+  async remove(id: number) {
+    const deposit = await this.repo.findOne({ where: { id } });
+    if (!deposit) throw new NotFoundException('押金记录不存在');
+    await this.repo.delete(id);
+    return { message: '删除成功' };
+  }
+
+  async getStats() {
+    const result = await this.repo.createQueryBuilder('d')
+      .select('d.status', 'status')
+      .addSelect('COUNT(*)', 'count')
+      .addSelect('SUM(d.amount)', 'totalAmount')
+      .groupBy('d.status')
+      .getRawMany();
+    return result;
+  }
+}