fix: 修复货币下拉列表无法展开问题，支持CNY/USD/HKD三种货币选择，选择股票时自动填充对应货币

pages/detail/detail.vue

@@ -200,10 +200,12 @@
           
           <view class="form-item">
             <text class="form-label">货币</text>
+            <picker @change="onCurrencyChange" :value="currencyIndex" :range="currencyList" range-key="name">
               <view class="form-select">
                 <text>{{ transactionForm.currency }}</text>
                 <uni-icons type="bottom" size="14" color="#9CA3AF"></uni-icons>
               </view>
+            </picker>
           </view>
           
           <view class="form-item">
@@ -264,13 +266,26 @@ const transactionForm = ref({
   remark: ''
 });
 
+// 货币选择相关
+const currencyList = ref([
+  { name: '人民币 CNY', code: 'CNY' },
+  { name: '美元 USD', code: 'USD' },
+  { name: '港币 HKD', code: 'HKD' }
+]);
+const currencyIndex = ref(0);
+
+const onCurrencyChange = (e) => {
+  currencyIndex.value = e.detail.value;
+  transactionForm.value.currency = currencyList.value[currencyIndex.value].code;
+};
+
 // 股票搜索相关
 const searchResults = ref([]);
 const searchTimer = ref(null);
 const searchStock = async (keyword) => {
   // 防抖
   if (searchTimer.value) clearTimeout(searchTimer.value);
-  if (!keyword || keyword.length < 2) {
+  if (!keyword || keyword.length < 1) {
     searchResults.value = [];
     return;
   }
@@ -289,7 +304,19 @@ const searchStock = async (keyword) => {
 };
 
 const selectStock = (result) => {
-  transactionForm.value.stockCode = result.Ticker;
+  transactionForm.value.stockCode = result.ticker || result.Ticker;
+  // 自动填充对应货币
+  if (result.priceCurrency) {
+    const currencyMap = {
+      'CNY': 0,
+      'USD': 1,
+      'HKD': 2
+    };
+    if (currencyMap[result.priceCurrency] !== undefined) {
+      currencyIndex.value = currencyMap[result.priceCurrency];
+      transactionForm.value.currency = result.priceCurrency;
+    }
+  }
   searchResults.value = [];
 };