Implement role cleanup on professor/student deletion to prevent orphaned user roles

[Copilot]

This PR addresses a critical data consistency issue where deleting a Professor or Student linked to a User would leave the User in an inconsistent state with orphaned roles.

Problem

Currently, when a Professor or Student is deleted, any linked User retains their Professor/Student role even though the corresponding entity no longer exists. This violates the system's constraint that users with Professor or Student roles must be linked to actual Professor/Student records.

For example, a user like this:

Would be left with the Professor role even after their associated Professor record is deleted, creating an inconsistent state.

Solution

This implementation adds before_destroy callbacks to both Professor and Student models that automatically handle role cleanup when these entities are deleted:

Key Features:

• Automatic role removal: When a Professor/Student is deleted, the corresponding role is removed from the linked user
• Graceful degradation: If the user has only the Professor/Student role, they automatically receive the "Desconhecido" (Unknown) role
• Multi-role support: Users with multiple roles keep their other roles and get their actual_role updated appropriately
• Edge case handling: No errors occur when deleting Professor/Student records without linked users

Code Changes:

# In Professor model
before_destroy :handle_user_role_removal

private
def handle_user_role_removal
  return unless user.present?
  
  # Remove professor role and handle role reassignment
  professor_role = Role.find_by(id: Role::ROLE_PROFESSOR)
  if professor_role && user.roles.include?(professor_role)
    user.roles.delete(professor_role)
    
    # Assign unknown role if no roles left
    if user.roles.empty?
      unknown_role = Role.find_by(id: Role::ROLE_DESCONHECIDO)
      user.roles << unknown_role if unknown_role
    end
    
    # Update actual_role appropriately
    if user.actual_role == Role::ROLE_PROFESSOR
      user.actual_role = user.user_max_role || Role::ROLE_DESCONHECIDO
    end
    
    user.save!
  end
  
  self.user = nil
end

Test Coverage:

• ✅ Professor with only Professor role → Gets "Desconhecido" role
• ✅ Professor with multiple roles → Keeps other roles, updates actual_role
• ✅ Student with only Student role → Gets "Desconhecido" role
• ✅ Student with multiple roles → Keeps other roles, updates actual_role
• ✅ Professor/Student without linked user → Normal deletion, no errors

Benefits

• Data consistency: Users always have valid role associations
• Administrative flexibility: Allows safe cleanup of professor/student records
• No breaking changes: Existing functionality is preserved
• Backward compatible: Works seamlessly with current user management

Fixes #574.

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[SAASVUUV]

Julguei que tinham testes desnecessários para validar a nova função. Além disso, na função handle_user_role_removal haviam validações para verificar se os roles de professor, aluno e desconhecido existiam, o que pra mim não fazia muito sentido, visto que são roles padrão do sistema (roles.rb). Por fim, ao final dessa função, ele limpava o atributo user de aluno/professor, sendo que de qualquer jeito a entidade vai ser destruída, além de que isso não é reproduzido em nenhuma função para :before_save.

Obs. A função em student.rb e professor.rb são semelhantes, mudando somente de aluno para professor, portanto as mudanças foram as mesmas em ambos.

Concordam com as alterações? Fariam mais alguma mudança?