style: Final glassmorphism polish for auto-hiding sidebar

frontend/components/Sidebar.tsx

@@ -45,7 +45,7 @@ export default function Sidebar({ tabs, activeTab, onTabSelect, status, lang }:
     <aside 
       onMouseEnter={() => setIsExpanded(true)}
       onMouseLeave={() => setIsExpanded(false)}
-      className={`glass-card rounded-3xl h-[calc(100vh-3rem)] sticky top-6 p-4 flex flex-col gap-8 transition-all duration-500 ease-in-out z-50 ${isExpanded ? 'w-72' : 'w-[84px] shadow-none border-white/5'}`}
+      className={`glass-card rounded-3xl h-[calc(100vh-3rem)] sticky top-6 p-4 flex flex-col gap-8 transition-all duration-500 ease-in-out z-50 border-white/10 ${isExpanded ? 'w-72 shadow-2xl shadow-purple-500/10 bg-black/60' : 'w-[84px] shadow-none border-white/5 bg-white/[0.02]'}`}
     >
       <div className={`flex items-center gap-3 px-2 transition-all duration-300 ${isExpanded ? 'justify-start' : 'justify-center'}`}>
         <div className="w-10 h-10 premium-gradient rounded-xl flex-shrink-0 flex items-center justify-center shadow-lg shadow-purple-500/20">