Feature: Add percent as unit in the metrics view

Hello.

**Enhancement**
Some metrics, like the one below, use the percent as a unit but it's currently not possible to select it in the UI.
Could you please add it? Thanks in advance.

<img width="1639" height="284" alt="Image" src="https://github.com/user-attachments/assets/5e798711-becd-454c-b064-df28f6273469" />
