UNO refactor (stage 2): responsive list/grid screens + chat

Make all menu screens use the width on desktop/landscape and the UNO panels:
- Shop item grid 3→up to 6 cols; BuyCoins packs 2→4 cols on lg.
- Lobby: panel league pick (2-col) + 2-col CTA buttons.
- Achievements / Notifications / Leaderboard / Friends lists → responsive
  grids (1 col mobile, 2 cols on lg); glass→panel on section containers.
- Chat: centered max-w-3xl column on desktop, green send button.
All responsive for mobile + desktop. tsc + build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/screens/ShopScreen.tsx

@@ -173,7 +173,7 @@ export function ShopScreen() {
           {Array.from({ length: 2 }).map((_, s) => (
             <div key={s}>
               <div className="h-4 w-24 rounded bg-navy-800/80 animate-pulse mb-3" />
-              <div className="grid grid-cols-3 gap-3">
+              <div className="grid grid-cols-3 sm:grid-cols-4 lg:grid-cols-6 gap-3">
                 {Array.from({ length: 3 }).map((_, i) => (
                   <div key={i} className="glass rounded-2xl p-3 flex flex-col items-center gap-2 animate-pulse">
                     <div className="size-12 rounded-xl bg-navy-800/80" />
@@ -192,7 +192,7 @@ export function ShopScreen() {
         if (!list.length) return null;
         return (
           <Section key={sec.kind} title={sec.title} hint={sec.hint}>
-            <div className="grid grid-cols-3 gap-3">
+            <div className="grid grid-cols-3 sm:grid-cols-4 lg:grid-cols-6 gap-3">
               {list.map((item) => (
                 <ItemCard key={item.id} item={item} owned={owns(item)} reqLabel={lockLabel(item)} onOpen={() => setDetail(item)} />
               ))}