You set a photo as the gallery cover. Days later you change your mind and want the auto-newest-approved fallback back. You open the lightbox on that photo and the cover button is sitting there disabled with a "Gallery cover" badge. There's no Clear button. The only way out used to be: open a different photo, click Set on it, then Undo through the success toast. Two clicks, one window of attention, and a kludge.
The cover buttons in the host lightbox now toggle. Set on photos that aren't the cover; Clear on the one that is. Clicking the Clear variant routes the same server action with a null photo id — the schema already accepted it; only the UI was missing the path back.
Both cover affordances behave the same way now: the album-cover button (the one that surfaces for photos that belong to a real album tab) and the gallery-wide cover button (the one that drives the OG link preview + the dashboard card thumbnail). Star icon flips to filled when the photo is the active cover, mirroring the amber-fill convention the host favorite and other active-state badges already use.
A small dead-end closed. If you never noticed the button going inert, you probably never needed it. If you did, this is the path that wasn't there.
