Selective / Dynamic highlighting line numbers

Selective and dynamic highlighting is currently relative to the rendered line numbers, it gets difficult to reason about when we have hidden lines. In this example, it would be very easy to know the target ranges with Vim's relative line numbers (starting with 5). The current workflow forces the author to enable `+line_numbers` and switch back and forth with the live presentation to know the exact ranges. <img width="1047" height="485" alt="Image" src="https://github.com/user-attachments/assets/527165a5-f2fb-41ae-9763-12f5c7140555" />