feat: 新增 money.ts 工具文件，提供基于 decimal.js 的精确金额计算和格式化功能。

src/utils/money.ts

@@ -75,16 +75,26 @@ export const Money = {
   },
 
   /**
-   * Format money for display with currency symbol
+   * Format money for display with currency symbol (Standard v7.0)
    */
   format(value: number | string, currency: string = 'CNY'): string {
-    const num = new Decimal(value).toDecimalPlaces(2).toNumber();
-    const symbol = CURRENCY_SYMBOLS[currency] || currency;
-    const formatted = num.toLocaleString('zh-CN', {
-      minimumFractionDigits: 2,
-      maximumFractionDigits: 2,
-    });
-    return `${symbol}${formatted}`;
+    const num = new Decimal(value).toNumber();
+    try {
+      return new Intl.NumberFormat('zh-CN', {
+        style: 'currency',
+        currency: currency,
+        minimumFractionDigits: 2,
+        maximumFractionDigits: 2,
+      }).format(num);
+    } catch (e) {
+      // Fallback for invalid currency codes
+      const symbol = CURRENCY_SYMBOLS[currency] || currency;
+      const formatted = num.toLocaleString('zh-CN', {
+        minimumFractionDigits: 2,
+        maximumFractionDigits: 2,
+      });
+      return `${symbol}${formatted}`;
+    }
   },
 
   /**