Open views naming the retired Snow style on Normal

createView threw on style 'snow', so an embed host or a
show_in_gods_eye_view call holding a view from before Snow was retired
was refused outright, camera and layers included. viewFromParams read
style=snow as the recipient's own style, while the app opened the same
link on Normal.

Both now read a retired style as Normal; truly unknown names still
throw. The retired list moves to a browser-free module shared by the
view API, the share codec and visual settings.

src/ui/visualPresets.js

@@ -17,12 +17,6 @@ export const STYLES = {
   noir: noirShader,
 };
 
-/**
- * Styles the app no longer offers. A share link, scene or shot that names one
- * opens on Normal instead of keeping whatever style was already showing.
- */
-export const RETIRED_STYLES = Object.freeze(['snow']);
-
 /**
  * The tactical detection look: Dense at 75%.
  *