- [x] [Task 6] User Recommended Major List API Integration <!-- id: 32 -->
- [x] [Task 8] Fix TypeScript type error in `simulate.vue` <!-- id: 36 -->
- [x] [Task 9] Volunteer Filling Logic Perfection <!-- id: 39 -->
    - [x] Encapsulate volunteer APIs (`src/service/api/volunteer.ts`) <!-- id: 40 -->
    - [x] Integrate save/detail logic in `simulate.vue` <!-- id: 41 -->
    - [x] Implement modification detection and leave protection <!-- id: 42 -->