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/sync/sync.service.ts

@@ -214,6 +214,6 @@ export class SyncService {
 
   private async performWeComSync(_lastSyncAt: Date | null): Promise<number> {
     const result = await this.weComService.syncAll();
-    return result.deptCount + result.userCount;
+    return result.userCount;
   }
 }