interactables/menu bg - demo update (v17)

• Added a new version of the interactable user interface - improving overall visibility, showing out-of-view targets and simplifying the appearance of light switches (the old version can be restored at "Options/Game/Interaction display version").
• Fixed "same room" determination for interactable UI, affecting their visibility.
• Updated the main menu background.
• Added clarifying hints to NPC light/sound tool tutorials.
• Various minor visual tutorial tweaks.

The full game is available on Steam.