feat(B4): 友链分组改下拉选已有+允许新建(Select allow-create filterable)

- options=数据聚合的既有分组;仍落 groupName 字符串,后端零改动
- 拼错旧组名不再产生新脏分组;vitest 25/25 绿+build 成功

src/views/cms/LinkManage.vue

@@ -191,7 +191,17 @@ watch(() => store.siteId, () => run());
         <Modal v-model="modalVisible" :title="form.id ? '编辑友链' : '新增友链'" :mask-closable="false" width="520px">
             <Form ref="formRef" :model="form" :rules="rules" :label-width="100">
                 <FormItem label="分组">
-                    <Input v-model="form.groupName" :maxlength="64" placeholder="上级部门/兄弟院校/合作单位…" />
+                    <!-- B4：下拉选已有分组 + 允许新建（仍落 groupName 字符串，后端零改动）；杜绝拼错旧组名产生脏分组 -->
+                    <Select
+                        v-model="form.groupName"
+                        filterable
+                        allow-create
+                        :maxlength="64"
+                        placeholder="选择已有分组，或输入新名称回车新建"
+                        style="width: 320px"
+                    >
+                        <Option v-for="g in groups" :key="g" :value="g">{{ g }}</Option>
+                    </Select>
                 </FormItem>
                 <FormItem label="名称" prop="name">
                     <Input v-model="form.name" :maxlength="128" />