剥离学校端/教师端/学生端/3D建模模块，清理跨模块引用
- 移除 backend: school/ (schools, departments, grades, classes, teachers, students)
- 移除 backend: ai-3d/ (controller, service, providers, utils)
- 移除 frontend: views/school/, views/workbench/ai-3d/, views/model/
- 移除 prisma schema: School, Grade, Department, Class, Teacher, Student, StudentInterestClass, AI3DTask 共8个模型
- 移除 app.module.ts: SchoolModule, AI3DModule 导入
- 移除 router/index.ts: 3D建模4条路由
- 移除 menu.ts: componentMap 中学校/3D映射
- 修复 registrations.service.ts: 教师判断从 Teacher 模型改为角色判断
- 修复 results.service.ts: 移除 student include
- 修复 homework services: 移除 student/class/grade 相关 Prisma 查询
- 保留 students.ts/teachers.ts/ai-3d.ts 最小类型存根供赛事组件引用
- 原始代码备份至 competition-management-system-stripped-modules/
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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