Add watchstar icon-button to the sticky header.
Background / motivation
the prototype has been updated (remember to log-in): https://di-community-round-2.web.app/Starry_Night_Over_the_Rh%C3%B4ne
- Clicking the watch star in the sticky header should behave the same as clicking it in the article toolbar
- Add watchstar functionality to the sticky header
- Under 1200px the sticky header should not display (this seems to have regressed at some point)
- The watchstar in the sticky header state should be in sync with the one outside the sticky header
- Go to a page which is not watched. Confirm the watchstar at the top of the page is not filled.
- Scroll so the sticky header displays.
- Click the watchstar in the sticky header
- Scroll to the top of the page, the watchstar outside the sticky header should be filled.
- Click the watchstar at the top of the page and scroll down the page to show the sticky header again
- Confirm the watchstar inside the sticky header is not filled.