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/chats/views/ChatView.vue

@@ -11,7 +11,7 @@ import {
   type ChatConversation,
   type ChatMessage,
 } from '@/api/chats'
-import { uploadFile } from '@/api/files'
+import { uploadFile } from '@/shared/api/files'
 import ChatAttachmentImage from '@/components/ChatAttachmentImage.vue'
 import { useChatSSE, type ChatEvent } from '@/composables/useChatSSE'
 import { formatDateMinute } from '@/utils/time'