feat(design): glass surfaces by role, the static Badge, LinkButton, user pickers on the Combobox (E28 S3d1)

frontend/src/design-lab/labKit.tsx

@@ -1,5 +1,6 @@
 import { useSyncExternalStore, type ReactNode } from "react";
 import clsx from "clsx";
+import { SURFACE } from "../components/ui/surfaces";
 
 // Building blocks of the design lab. Every E28 decision is taken, so the lab is the reference half
 // only: each <Reference> is the chosen rendering with the rule it became. A new design round brings
@@ -22,7 +23,7 @@ export function Reference({
   children: ReactNode;
 }) {
   return (
-    <section id={id} className="glass-card rounded-xl p-4 flex flex-col gap-3 scroll-mt-20">
+    <section id={id} className={`${SURFACE.card} p-4 flex flex-col gap-3 scroll-mt-20`}>
       <header>
         <div className="flex items-baseline gap-3">
           <span className="text-xs font-bold tracking-widest text-success">{code} ✓</span>