fix: wrong record loss duration

src/components/device-page/device-card/current-diag-card/nvr-record-diag-card.vue

@@ -99,16 +99,25 @@ const formatTime = (timeStr: string) => {
 const formatDuration = (startTime: string, endTime: string) => {
   const start = dayjs(startTime);
   const end = dayjs(endTime);
-  const diff = end.diff(start);
-  const dur = dayjs.duration(diff);
+  const diffMs = end.diff(start);
 
-  if (dur.asHours() >= 1) {
-    return `${Math.floor(dur.asHours())}小时${dur.minutes()}分钟`;
-  } else if (dur.asMinutes() >= 1) {
-    return `${dur.minutes()}分钟${dur.seconds()}秒`;
+  const isNegative = diffMs < 0;
+  const durAbs = dayjs.duration(Math.abs(diffMs));
+
+  const hours = Math.floor(durAbs.asHours());
+  const minutes = durAbs.minutes();
+  const seconds = durAbs.seconds();
+
+  let result: string;
+  if (hours > 0) {
+    result = `${hours}小时${minutes}分${seconds}秒`;
+  } else if (minutes > 0) {
+    result = `${minutes}分${seconds}秒`;
   } else {
-    return `${dur.seconds()}秒`;
+    result = `${seconds}秒`;
   }
+
+  return isNegative ? `-${result}` : result;
 };
 
 /**