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/entities/index.ts

@@ -26,8 +26,6 @@ export { SyncLog } from './sync-log.entity';
 export { SyncState } from './sync-state.entity';
 export { ExpenseType } from './expense-type.entity';
 export { Notification, NotificationType } from './notification.entity';
-export { Department, DepartmentType } from './department.entity';
-export { UserDepartment } from './user-department.entity';
 export { StudentProfile } from './student-profile.entity';
 export { StudentEnrollment } from './student-enrollment.entity';
 export { ExamScore } from './exam-score.entity';