feat: 优化大厅期号倒计时并改用服务端时间同步

src/types/api/draw-current.ts

@@ -36,3 +36,9 @@ export type DrawCurrentPayload = {
   result_version?: number;
   result_source?: string | null;
 };
+
+/** `GET /api/v1/draw/current` 的完整响应 */
+export type DrawCurrentResponse = {
+  server_now_ms: number;
+  data: DrawCurrentPayload | null;
+};