refactor(PersonPickerField): 重构搜索逻辑并修复回车搜索处理

- 抽离核心搜索逻辑为可复用的 runSearch 函数
- 将回车触发事件从 keyup.enter 调整为 keydown.enter.prevent.stop，并新增专用处理函数
- 弹窗打开和清空搜索框时自动执行空关键词搜索

@@ -44,7 +44,7 @@
             class="search-input-field"
             placeholder="请输入姓名、法名、手机号或证件号"
             :border="false"
-            @keyup.enter="onSearch"
+            @keydown.enter.prevent.stop="onSearchEnter"
           >
             <template #button>
               <div class="search-bar-actions">
@@ -275,6 +275,9 @@ const openPopup = async () => {
   draftPersons.value = _.cloneDeep(confirmedPersons.value);
   resetSearchState();
   showPopup.value = true;
+  await runSearch({
+    keyword: '',
+  });
 };
 
 const onCancelClick = () => {
@@ -332,6 +335,9 @@ const onSearchResultChange = (checkedIds) => {
 
 const onClearSearch = () => {
   resetSearchState();
+  runSearch({
+    keyword: '',
+  });
 };
 
 /**
@@ -420,13 +426,8 @@ const updateFinishedStatus = (pageData, total) => {
 /**
  * 执行一次新的搜索，并重置分页状态。
  */
-const onSearch = async () => {
-  const keyword = searchKeyword.value.trim();
-  if (!keyword) {
-    showToast('请输入搜索关键词');
-    return;
-  }
-
+const runSearch = async ({ keyword }) => {
+  searchKeyword.value = keyword;
   searching.value = true;
   hasSearched.value = true;
   loading.value = true;
@@ -448,6 +449,17 @@ const onSearch = async () => {
   }
 };
 
+const onSearch = async () => {
+  const keyword = searchKeyword.value.trim();
+  await runSearch({
+    keyword,
+  });
+};
+
+const onSearchEnter = async () => {
+  await onSearch();
+};
+
 /**
  * 加载下一页搜索结果。
  */