perf: render only first 50? entries in ItemUsage

With a 'show more' button to show the rest. Copy behaviour from Firefox DevTools because it's fast and works well.

<img width="405" height="362" alt="Image" src="https://github.com/user-attachments/assets/3d97d586-393c-4f01-95b4-bd60ec7b0d9e" />

<img width="1076" height="472" alt="Image" src="https://github.com/user-attachments/assets/2f136fe4-00c9-4182-90c4-cfb92bbb3414" />

