Update styling of Share and Publish menus to match the rest of the app

The square corners in "Copy link" don't seem to match our styling:

<img width="642" height="231" alt="Image" src="https://github.com/user-attachments/assets/dbe335bb-5348-44b5-b67e-172730dcee5f" /><br>

Ditto on the square corners and lack of icon:


<img width="1032" height="332" alt="Image" src="https://github.com/user-attachments/assets/5b3bbf0e-719a-4aa2-a27a-308f815d7c8a" />

