chore: 批量更新导入路径到 features 架构

- 更新所有 admin API 文件导入路径
- 更新所有 features 中 Vue 文件的导入路径
- 修复 ChatAttachmentImage 组件导入
- 修复 auth 模块部分导入路径

剩余 ~190 个类型错误待修复（主要是缺失的模块）

frontend/src/features/admin/components/AssignRolesDialog.vue

@@ -2,8 +2,8 @@
 import { ElMessage } from 'element-plus'
 import { ref, watch } from 'vue'
 
-import { fetchRoles, type Role } from '@/api/adminRoles'
-import { assignAdminRoles, type AdminMgrUser } from '@/api/adminMgr'
+import { fetchRoles, type Role } from '@/features/admin/api/adminRoles'
+import { assignAdminRoles, type AdminMgrUser } from '@/features/admin/api/adminMgr'
 
 const props = defineProps<{
   modelValue: boolean