fix: 修复大厅倒计时空数据覆盖问题

src/features/hall/use-hall-draw-live.ts

@@ -74,6 +74,12 @@ export function useHallDrawLive(): HallDrawLiveSnapshot {
     setEmittedAtMs(evt.emitted_at_ms ?? Date.now());
   }, []);
 
+  const mergeCountdownFromWs = useCallback((evt: HallWsEnvelope) => {
+    if (evt.data === null) return;
+    setRaw(evt.data);
+    setEmittedAtMs(evt.emitted_at_ms ?? Date.now());
+  }, []);
+
   const updateFromResponse = useCallback((resp: DrawCurrentResponse) => {
     setServerNowMs(resp.server_now_ms);
     setRaw(resp.data);
@@ -123,7 +129,7 @@ export function useHallDrawLive(): HallDrawLiveSnapshot {
     const channel = echo.channel("lottery-hall");
 
     // 设置事件监听
-    channel.listen(".draw.countdown", mergeFromWs);
+    channel.listen(".draw.countdown", mergeCountdownFromWs);
     channel.listen(".draw.status_change", mergeFromWs);
     channel.listen(".result.published", (evt: HallWsEnvelope) => {
       // 开奖结果发布时触发钱包轮询
@@ -187,6 +193,7 @@ export function useHallDrawLive(): HallDrawLiveSnapshot {
       }
     };
   }, [
+    mergeCountdownFromWs,
     mergeFromWs,
     load,
     setDrawPollingIntervalId,