fix(frontend): 修复操作日志与数据转换类型错误，修正普通用户角色取值

- OperationLogView: showDetail 调用补充 OperationLog 类型断言
- DataConvertView: beforeUpload 参数类型改为 UploadRawFile 并直接读取 file.type
- UserCreateView: 普通用户角色值 user 修正为 operator

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/views/audit/OperationLogView.vue

@@ -313,7 +313,7 @@ onMounted(() => {
       </el-table-column>
       <el-table-column label="操作" width="80" align="center" fixed="right">
         <template #default="{ row }">
-          <el-button link type="primary" size="small" @click="showDetail(row)">详情</el-button>
+          <el-button link type="primary" size="small" @click="showDetail(row as OperationLog)">详情</el-button>
         </template>
       </el-table-column>
     </el-table>

frontend/src/views/data-convert/DataConvertView.vue

@@ -2,7 +2,7 @@
 import { onMounted, ref } from 'vue'
 import { ElMessage, ElMessageBox } from 'element-plus'
 import { Plus, Delete, Refresh } from '@element-plus/icons-vue'
-import type { TagProps, UploadRequestOptions, UploadFile } from 'element-plus'
+import type { TagProps, UploadRequestOptions, UploadFile, UploadRawFile } from 'element-plus'
 import PageCard from '@/components/PageCard.vue'
 import {
   getDataConvertTasks,
@@ -30,9 +30,9 @@ async function load() {
 }
 
 // 文件上传前的校验（仅校验文件格式）
-function beforeUpload(file: UploadFile) {
+function beforeUpload(file: UploadRawFile) {
   // 检查文件类型
-  const isJson = file.name.endsWith('.json') || file.raw?.type === 'application/json'
+  const isJson = file.name.endsWith('.json') || file.type === 'application/json'
   if (!isJson) {
     ElMessage.error('只能上传 .json 格式的文件')
     return false

frontend/src/views/system/UserCreateView.vue

@@ -12,7 +12,7 @@ const form = reactive<CreateUserPayload>({
   username: '',
   display_name: '',
   password: 'platform123',
-  role: 'user',
+  role: 'operator',
   status: 'active',
   permissions: [],
 })
@@ -45,7 +45,7 @@ async function submit() {
       <el-form-item label="角色">
         <el-select v-model="form.role" style="width: 100%">
           <el-option label="管理员" value="admin" />
-          <el-option label="普通用户" value="user" />
+          <el-option label="普通用户" value="operator" />
         </el-select>
       </el-form-item>
       <el-form-item label="状态">