Fix confusing desktop behavior in expanded photo carousel

The expanded photo carousel has several confusing desktop interactions around navigation, scrolling, and closing.

Transcript Context

The team reported that the bottom media strip in the expanded carousel does not show usable arrows on web, and dragging is not possible on desktop. They also described confusing behavior at the end of the carousel, where clicks can unexpectedly open an image or otherwise behave differently than expected. Another reported issue was that closing the expanded carousel could leave the user in a different section than expected. The request is to make desktop navigation predictable and obvious.

Missing arrows:

End of carousel:

Screen Recording 2026-05-05 at 8.57.25 AM.mov

Closing carousel:

Screen Recording 2026-05-05 at 8.59.53 AM.mov