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/BuyCoinsScreen.tsx

@@ -128,7 +128,7 @@ export function BuyCoinsScreen() {
         <div className="mb-4 text-center text-cream/80 text-sm glass rounded-xl py-2">{msg}</div>
       )}
 
-      <div className="grid grid-cols-2 gap-3 pb-6">
+      <div className="grid grid-cols-2 lg:grid-cols-4 gap-3 pb-6">
         {packs.map((p) => (
           <button
             key={p.id}