fix: 创建组合时正确传递持仓币种

1. 新增 inferCurrencyFromCode 函数，根据股票代码推断币种
   - .US/.NYSE/.NASDAQ → USD
   - .HK/.HKEX → HKD
   - .SZ/.SH 或 6 位数字 → CNY
   - 加密货币 → USD

2. 搜索股票时映射 priceCurrency 字段
3. 选择股票时保存 currency 到表单
4. 提交时同时传递 assetType 字段

pages/config/config.vue

@@ -187,6 +187,7 @@ interface SearchResult {
   name?: string;
   exchange?: string;
   assetType?: string;
+  currency?: string;
   stockIndex: number;
 }
 
@@ -230,7 +231,11 @@ const searchStock = async (keyword: string, stockIndex: number): Promise<void> =
     try {
       const res = await api.ticker.search(keyword);
       if (res.code === 200) {
-        searchResults.value = res.data.map((item: any) => ({ ...item, stockIndex }));
+        searchResults.value = res.data.map((item: any) => ({ 
+          ...item, 
+          stockIndex,
+          currency: item.priceCurrency || item.currency // 映射币种字段
+        }));
       }
     } catch {
       searchResults.value = [];
@@ -244,6 +249,7 @@ const selectStock = (result: SearchResult): void => {
   if (stock) {
     stock.name = result.ticker;
     stock.assetType = result.assetType;
+    stock.currency = result.currency; // 保存搜索结果中的币种
   }
   searchResults.value = [];
   activeSearchIndex.value = -1;
@@ -353,6 +359,30 @@ const submitForm = async (): Promise<void> => {
     }
   }
   
+// 根据股票代码推断币种
+const inferCurrencyFromCode = (code: string): string => {
+  if (!code) return selectedCurrency;
+  const upperCode = code.toUpperCase();
+  // 美股
+  if (upperCode.endsWith('.US') || upperCode.endsWith('.NYSE') || upperCode.endsWith('.NASDAQ')) {
+    return 'USD';
+  }
+  // 港股
+  if (upperCode.endsWith('.HK') || upperCode.endsWith('.HKEX')) {
+    return 'HKD';
+  }
+  // A股
+  if (upperCode.endsWith('.SZ') || upperCode.endsWith('.SH') || /^[0-9]{6}$/.test(upperCode)) {
+    return 'CNY';
+  }
+  // 加密货币默认 USD
+  if (upperCode.includes('BTC') || upperCode.includes('ETH') || upperCode.includes('USDT')) {
+    return 'USD';
+  }
+  // 默认使用组合本位币
+  return selectedCurrency;
+};
+
   const selectedCurrency = currencyList.value[currencyIndex.value].code;
   const requestData = {
     name: form.value.name,
@@ -364,7 +394,8 @@ const submitForm = async (): Promise<void> => {
       price: parseFloat(stock.price) || 0,
       amount: parseFloat(stock.amount) || 0,
       date: stock.date,
-      currency: selectedCurrency
+      currency: stock.currency || inferCurrencyFromCode(stock.name),
+      assetType: stock.assetType || 'Stock'
     }))
   };