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

frontend/src/components/LanguageSwitcher.tsx

@@ -4,6 +4,7 @@ import { LANGUAGES, type LangCode } from "../i18n";
 import { PopoverItem, PopoverSurface } from "./ui/AnchoredPopover";
 import { useAnchoredPopover } from "./ui/anchoredPopoverHooks";
 import { Pressable } from "./ui/Pressable";
+import { SURFACE } from "./ui/surfaces";
 
 // Compact language picker (globe + current code). Presentational: the parent decides what
 // changing the language does (set it; persist server-side when signed in).
@@ -67,10 +68,7 @@ export default function LanguageSwitcher({
         )}
       </Pressable>
 
-      <PopoverSurface
-        popover={pop}
-        className="glass-menu w-40 rounded-xl p-1.5 animate-[popIn_0.16s_ease]"
-      >
+      <PopoverSurface popover={pop} className={`${SURFACE.menu} w-40 animate-[popIn_0.16s_ease]`}>
         {LANGUAGES.map((l) => (
           <PopoverItem
             key={l.code}