FAC-95 FAC-96 refactor: curriculum service filter type safety and search deduplication

[y4nder]

Summary

• FAC-95 (FAC-95 refactor: unsafe type assertions bypass MikroORM filter type-checking #210): Replace Record<string, unknown> + as FilterQuery<T> casts with properly typed FilterQuery<Department> and FilterQuery<Program> intermediates in ListPrograms and ListCourses, restoring MikroORM compile-time type safety
• FAC-96 (FAC-96 refactor: search filter construction duplicated across all three service methods #211): Extract the duplicated 12-line $and/$or/$ilike search filter block into a shared ApplySearchFilter private helper, used by all three list methods

Test plan

• All 32 existing curriculum service tests pass
• TypeScript build succeeds
• Verify no runtime regression on list endpoints (departments, programs, courses) with and without search queries

Closes #210
Closes #211

https://claude.ai/code/session_01Y6eWhKjmgLfPJQMJa4VQQB