According to the patch notes this is the function of the storage area by the corvette terminal
So it acts mostly as a safety net if you bulk buy some parts with a full inventory.
The ships can be upgraded at the regular starship terminal, as well as dis-assembled.
I’ve yet to try this though, so I’m not sure if it refunds all parts or just some, but this is where you would do it.
I might just make a quick peice of jank ship and test this out now 
Nevermind, the salvage analysis reveals the corvettes cannot be salvaged from this terminal.
It seems the only way for now is exchange a corvette for a regular ship and then scrap that. But you won’t get anything back so… Wait until they patch in a corvette disassembler I guess.
I was thinking about this as well as NPC Corvettes. They would either need to have some presets it can draw from, or have something in place that can proc gen a believable ship design from the parts available.
I don’t think they have anything like the latter in place, but if they can pull it off it’s definitely now very high on my wish list.
The windows look like they have things covering them up when building but will be transparent when constructed.
Doors are added automatically when habs and hallways are joined.