Give room contributors a tab in the “this room” page & allow contributors themselves to be hidden from the carousel or not
Then have it so that when a player creates/spawns anything in a room that remains in the published save, they’re shown in the contributor page depending on whether they wanted to or not
This should be purely cosmetic if the player is no longer contributor, otherwise it would behave normally
And make sure this persists through room clones
Speaking of clones, inventions should also only be transferable if the owner (creator or purchaser) of the invention is still a actual (not cosmetic one) contributor of said room, otherwise it should prompt the user to purchase said invention otherwise the entirety of the invention would be removed from the new clone
I feel like this would better credit contributors & protect invention creators