refactor(server): remove Department/UserDepartment entities, CampusScope, and departmentId from all entities

- Delete department.entity.ts, user-department.entity.ts
- Remove Department/UserDepartment from entities/index.ts
- Remove departmentId column from 18 entities (AttendanceRecord, ArchiveAttachment, Bill, ClassSchedule, Classroom, ClassroomRental, Deposit, DepositInstallment, ExamScore, LearningRecord, Occupancy, PersonalExpense, ResultArchive, Room, RoomExpense, Student, StudentEnrollment, StudentProfile, StudentReport)
- Remove departments/ module entirely
- Delete campus-scope.ts, campus-scope.middleware.ts (request-utils.ts kept — it's just IP extraction)
- Simplify common.module.ts to empty module
- Remove CampusScopeMiddleware from app.module.ts
- Remove all CampusScope injections and filter calls across all services
- Remove departmentId from all DTOs and controllers
- Simplify dingtalk/wecom sync to only sync users (no dept table)
- Update seed module to remove department seeding
- Clean frontend compilation

apps/server/src/main.ts

@@ -1,16 +1,12 @@
 import { NestFactory } from '@nestjs/core';
 import { ValidationPipe } from '@nestjs/common';
-import { DataSource } from 'typeorm';
 import { AppModule } from './app.module';
-import { seedDefaultCampus } from './departments/seed';
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
   app.setGlobalPrefix('api');
   app.enableCors();
   app.useGlobalPipes(new ValidationPipe({ transform: true, whitelist: true }));
-  const dataSource = app.get(DataSource);
-  await seedDefaultCampus(dataSource);
   await app.listen(process.env.PORT ?? 3000);
   console.log(`Server running on http://localhost:${process.env.PORT ?? 3000}`);
 }