Suggestion: Reframe "Amber" nodes to "Echo" supercategory; include "Infected" nodes

Now that I've completed the new story, I think it would make more sense to list the magic royal highland nodes covered in yellow goop (aka "amber echo", a type of echo that traps creatures in time or personal memory) in the same supercategory as the magic elderwood nodes covered in purple goop (aka "infected essence", a type of Echo that parasitically imparts another's emotions and will). I suspect we will encounter further kinds of echo in subsequent areas. A good name for this category (for now) would be "Echo".