feat(watchlist): add card view + toolbar parity to Bounties tab

## Summary

The Watchlist **Bounties** tab only has a list view. Add a **list / cards** view toggle like  bounties page

<img width="1411" height="872" alt="Image" src="https://github.com/user-attachments/assets/dbf9dda0-7efb-4f5e-a9a4-3fe3b80a1f75" />