feat: 更新 @kevisual/router 版本至 0.0.89；添加 download 命令模块以支持文件下载

assistant/src/main.ts

@@ -5,5 +5,6 @@ import './routes/index.ts';
 import './routes-simple/index.ts';
 
 export const AgentPlugin: Plugin = createRouterAgentPluginFn({
-  router: app,
-})
+  router: app as any,
+})
+export { app }