docs: 添加项目截图并更新next-env.d.ts路径

添加4张项目截图到README文档中，展示项目功能
更新next-env.d.ts中的类型声明文件路径

next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
+import "./.next/dev/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.