I've been experimenting with the custom Adventures format. As can be seen from the image on the front page, it's possible to code an ineractive chest box that the character can take items from (and possibly put items in). However, I can't figure out how to do this. I think there might be something in the source code, particularly surrounding the lootableInventory sections, but I don't really know.
In the Basic Usage > Items section of the documentation it mentions the ability to "spawn items in a small chest under the content of the passage", it then shows an example of using the story.addLootItem() function to add some "loot" related items to the current Passage.
Doing the above will cause the "chest-panel" to be show, which supports using the mouse to drag-n-drop items to & from it.