feat: 更新环境变量配置，添加 API 代理支持，新增 API 接口文件

src/api/index.ts

@@ -0,0 +1,6 @@
+import type { App } from "@riwa/api-types";
+import { treaty } from "@elysiajs/eden";
+
+const api = treaty<App>(`${window.location.origin}/api`);
+
+export { api };