Step UX-1：通用选择器

frontend/src/components/DataQueryForm.vue

@@ -5,9 +5,7 @@
         <el-input v-model="form.title" />
       </el-form-item>
       <el-form-item label="受试者" prop="subject_id">
-        <el-select v-model="form.subject_id" placeholder="可留空" clearable filterable>
-          <el-option v-for="s in subjects || []" :key="s.id" :label="s.subject_no || s.id" :value="s.id" />
-        </el-select>
+        <SubjectSelect v-model="form.subject_id" :study-id="study.currentStudy?.id || null" placeholder="可选" />
       </el-form-item>
       <el-form-item label="类别" prop="category">
         <el-select v-model="form.category" placeholder="请选择">
@@ -25,7 +23,7 @@
         </el-select>
       </el-form-item>
       <el-form-item label="指派给" prop="assigned_to">
-        <el-input v-model="form.assigned_to" placeholder="用户ID，可留空" />
+        <UserSelect v-model="form.assigned_to" placeholder="可选" />
       </el-form-item>
       <el-form-item label="截止日期" prop="due_date">
         <el-date-picker v-model="form.due_date" type="date" value-format="YYYY-MM-DD" />
@@ -47,14 +45,13 @@ import type { FormInstance, FormRules } from "element-plus";
 import { ElMessage } from "element-plus";
 import { createDataQuery, updateDataQuery } from "../api/dataQueries";
 import { useStudyStore } from "../store/study";
+import SubjectSelect from "./selectors/SubjectSelect.vue";
+import UserSelect from "./selectors/UserSelect.vue";
 
-interface Props {
+const props = defineProps<{
   modelValue: boolean;
   query?: Record<string, any>;
-  subjects?: any[];
-}
-
-const props = defineProps<Props>();
+}>();
 const emit = defineEmits(["update:modelValue", "success"]);
 
 const visible = computed({