feat(web): refresh palette, simplify ranking toolbar and drop export

reaction_board/web/static/favicon.svg

@@ -1,6 +1,6 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
   <defs><linearGradient id="g" x1="0" y1="0" x2="1" y2="1">
-    <stop offset="0" stop-color="#fb7299"/><stop offset="1" stop-color="#ff9fbc"/>
+    <stop offset="0" stop-color="#e9b97c"/><stop offset="1" stop-color="#c98e52"/>
   </linearGradient></defs>
   <rect width="64" height="64" rx="18" fill="url(#g)"/>
   <text x="32" y="42" font-size="34" font-weight="700" text-anchor="middle"