Change remaining budget label

Change "남은 예산" to "잔액" or "초과액" and update the piggy bank icon.

src/components/analytics/SummaryCards.tsx

@@ -1,6 +1,6 @@
 
 import React from 'react';
-import { Wallet, CreditCard, PiggyBank } from 'lucide-react';
+import { Wallet, CreditCard, Coins } from 'lucide-react';
 import { formatCurrency } from '@/utils/formatters';
 import { useIsMobile } from '@/hooks/use-mobile';
 
@@ -43,12 +43,12 @@ const SummaryCards: React.FC<SummaryCardsProps> = ({
       </div>
       <div className="neuro-card w-full">
         <div className="flex items-center gap-2 mb-1 py-[5px]">
-          <PiggyBank size={24} className="text-gray-500" />
-          <p className="text-gray-500 text-base">남은 예산</p>
+          <Coins size={24} className="text-gray-500" />
+          <p className="text-gray-500 text-base">잔액</p>
         </div>
         {isOverBudget ? (
           <p className="text-sm font-bold text-red-500">
-            예산 초과: {formatCurrency(Math.abs(remainingBudget))}
+            초과액: {formatCurrency(Math.abs(remainingBudget))}
           </p>
         ) : (
           <p className="text-sm font-bold text-neuro-income">