优化Link控件下拉数据加载机制

frontend/src/core/components/form/controls/Link.vue

@@ -186,10 +186,15 @@ function handleInputChange(value: string) {
 }
 
 // 处理输入框点击
-function handleInputClick() {
+async function handleInputClick() {
   if (!props.canEdit) return
+  
+  // 防止重复调用
+  if (showDropdown.value) return
+  
+  // 先加载数据，再显示下拉框
+  await searchOptions(searchQuery.value)
   showDropdown.value = true
-  searchOptions(searchQuery.value)
 }
 
 // 处理选项选择
@@ -260,7 +265,7 @@ onUnmounted(() => {
     </label>
     
     <div class="link-field-container" @mouseenter="showLinkButtons" @mouseleave="hideLinkButtons">
-      <div class="input-wrapper" @click="handleInputClick">
+      <div class="input-wrapper">
         <n-input 
           :value="hasValue ? displayValue : searchQuery" 
           :placeholder="ctx.t(df.fieldname)"