Add getSemesters endpoint and related data access
Introduce a new getSemesters endpoint in UserController.cs to retrieve user semester data using JWT authentication.
Add DbSet<EnrolledSemesters> to AppDbContext.cs for database interaction.
Implement GetUserSemestersAsync in UserRepository.cs to fetch semesters by user ID, and update IUserRepository.cs to declare this method.
Add GetUserSemesters method in UserService.cs to extract user ID from JWT and retrieve semesters, updating IUserService.cs accordingly.