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

frontend/src/components/NavSidebar.tsx

@@ -21,6 +21,7 @@ import LanguageSwitcher from "./LanguageSwitcher";
 import { PopoverSurface } from "./ui/AnchoredPopover";
 import { useAnchoredPopover } from "./ui/anchoredPopoverHooks";
 import { Pressable } from "./ui/Pressable";
+import { SURFACE } from "./ui/surfaces";
 
 // Primary app navigation: a thin icon-only left rail. The modules used to hide under the avatar
 // dropdown; they now live here, each revealing its name in a hover/focus flyout label. Account
@@ -202,7 +203,7 @@ export default function NavSidebar({
     // The slot is exactly the card's width so the filter tab/bar docks flush against its right edge.
     <div className="relative shrink-0 w-14">
       <nav
-        className="glass absolute top-0 bottom-0 left-0 z-rail rounded-2xl flex flex-col py-3 my-3 w-14 px-2"
+        className={`${SURFACE.panel} absolute top-0 bottom-0 left-0 z-rail flex flex-col py-3 my-3 w-14 px-2`}
         aria-label={t("nav.primary")}
       >
         <div
@@ -270,7 +271,7 @@ export default function NavSidebar({
             <PopoverSurface
               popover={acctPop}
               ariaLabel={name}
-              className="glass w-60 rounded-xl p-3 animate-[popIn_0.16s_ease]"
+              className={`${SURFACE.popover} w-60 p-3 animate-[popIn_0.16s_ease]`}
             >
               <div className="flex items-center gap-3 pb-3 border-b border-border">
                 <AvatarImg