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/integration/integration.module.ts

@@ -1,11 +1,11 @@
 import { Module } from '@nestjs/common';
 import { TypeOrmModule } from '@nestjs/typeorm';
-import { Department, User, Student, StudentDingMapping, Class } from '../entities';
+import { User, Student, StudentDingMapping, Class } from '../entities';
 import { DingTalkService } from './dingtalk.service';
 import { WeComService } from './wecom.service';
 
 @Module({
-  imports: [TypeOrmModule.forFeature([Department, User, Student, StudentDingMapping, Class])],
+  imports: [TypeOrmModule.forFeature([User, Student, StudentDingMapping, Class])],
   providers: [DingTalkService, WeComService],
   exports: [DingTalkService, WeComService],
 })