A conversation's shared media

Reached from the details hub.

Every example starts from saved, the checkpoint the index describes; the launch hands the feed, and a tab edge lands on the tab's root.

The hub's shared media is the list the details README's example opens (openSharedMedia()); its enter sends the thread's media pages on the thread's first visit only, and a group thread's openGroupNameEditor() continues into the group name editor.

The shared media of a conversation, opened by openSharedMedia().