perf(frontend): add lazy loading to profile and wallet images

Set loading=lazy on Avatar and wallet icon img elements to defer
offscreen image requests until users scroll them into view.

Author: Mosas2000

frontend/src/components/Avatar.tsx

@@ -49,6 +49,7 @@ export const Avatar: React.FC<AvatarProps> = ({
         <img
           src={avatarUrl}
           alt={name}
+          loading="lazy"
           className="w-full h-full object-cover"
           onError={() => {
             setHasImageError(true);

frontend/src/providers/WalletProvider.tsx

@@ -206,7 +206,7 @@ export const WalletProvider: React.FC<{ children: React.ReactNode }> = ({ childr
                 >
                   <div className="flex items-center gap-3">
                     {wallet.icon ? (
-                      <img src={wallet.icon} alt={wallet.name} className="h-6 w-6 rounded" />
+                      <img src={wallet.icon} alt={wallet.name} loading="lazy" className="h-6 w-6 rounded" />
                     ) : (
                       <div className="h-6 w-6 rounded bg-white/10" />
                     )}