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/share/viewCodec.js

@@ -31,9 +31,9 @@ import {
 } from '../data/detectionPolicy.js';
 import { clampScopeFeatherPct } from '../scopeMaskPolicy.js';
 import { VIEW_STYLES } from '../view/index.js';
+import { RETIRED_STYLES } from '../visualStylePolicy.js';
 import {
   GLOBAL_POST_DEFAULTS,
-  RETIRED_STYLES,
   STYLE_PRESET_DEFAULTS,
   STYLES,
 } from '../ui/visualPresets.js';