Major update: synth styles, gradient sets, export dialogs, glass UI, docs

- Synth styles: blend any two renderers with five mix operations into
  brand-new generated looks, savable to localStorage as style chips
- Share codes bumped to v2 (synth fields), v1 codes still decode
- Gradient set generator: 4-12 seed variations with preview grid and
  ZIP batch download via a dependency-free store-only ZIP writer
- Export buttons now open dialogs with live preview and settings
- UI redesign: glassy translucent surfaces, rounder geometry, staggered
  intro animation, hover micro-interactions, refined scrollbars
- Docs page, generated favicon/touch icons and OG image, meta tags
- Skip chromatic aberration during synth blends to keep the D3D shader
  linker under its inlining limit

Co-authored-by: Cursor <cursoragent@cursor.com>

js/exporter.js

@@ -91,7 +91,7 @@ var Exporter = (function () {
   async function exportVideo(P, aspect) {
     if (busy) return;
     if (typeof VideoEncoder === "undefined" || typeof VideoFrame === "undefined") {
-      UI.toast("This browser has no WebCodecs support \u2014 use a current Chrome, Edge or Firefox");
+      UI.toast("This browser has no WebCodecs support, use a current Chrome, Edge or Firefox");
       return;
     }
     busy = true;