Completed reminders cannot be deleted.

The CLI does not allow deletion of completed reminders.

<img width="653" alt="Image" src="https://github.com/user-attachments/assets/cc80d6ce-13bc-41ac-ad68-d4a64a9d3832" />

<img width="684" alt="Image" src="https://github.com/user-attachments/assets/d4414bb0-03ab-4e23-b2fc-ff605d957978" />