refactor(ops): 简化自动刷新定时器逻辑

- 合并双定时器为单一倒计时定时器
- 倒计时归零时触发数据刷新
- 添加自定义时间范围的安全回退

frontend/src/views/admin/ops/OpsDashboard.vue

@@ -355,23 +355,21 @@ const autoRefreshCountdown = ref(0)
 // Used to trigger child component refreshes in a single shared cadence.
 const dashboardRefreshToken = ref(0)
 
-// Auto refresh timer
-const { pause: pauseAutoRefresh, resume: resumeAutoRefresh } = useIntervalFn(
-  () => {
-    if (autoRefreshEnabled.value && opsEnabled.value && !loading.value) {
-      fetchData()
-    }
-  },
-  autoRefreshIntervalMs,
-  { immediate: false }
-)
-
-// Countdown timer (updates every second)
+// Countdown timer (drives auto refresh; updates every second)
 const { pause: pauseCountdown, resume: resumeCountdown } = useIntervalFn(
   () => {
-    if (autoRefreshEnabled.value && autoRefreshCountdown.value > 0) {
-      autoRefreshCountdown.value--
+    if (!autoRefreshEnabled.value) return
+    if (!opsEnabled.value) return
+    if (loading.value) return
+
+    if (autoRefreshCountdown.value <= 0) {
+      // Fetch immediately when the countdown reaches 0.
+      // fetchData() will reset the countdown to the full interval.
+      fetchData()
+      return
     }
+
+    autoRefreshCountdown.value -= 1
   },
   1000,
   { immediate: false }
@@ -477,12 +475,19 @@ function buildApiParams() {
     group_id: groupId.value ?? undefined,
     mode: queryMode.value
   }
-  if (timeRange.value === 'custom' && customStartTime.value && customEndTime.value) {
-    params.start_time = customStartTime.value
-    params.end_time = customEndTime.value
+
+  if (timeRange.value === 'custom') {
+    if (customStartTime.value && customEndTime.value) {
+      params.start_time = customStartTime.value
+      params.end_time = customEndTime.value
+    } else {
+      // Safety fallback: avoid sending time_range=custom (backend may not support it)
+      params.time_range = '1h'
+    }
   } else {
     params.time_range = timeRange.value
   }
+
   return params
 }
 
@@ -679,7 +684,6 @@ onMounted(async () => {
 
   // Start auto refresh if enabled
   if (autoRefreshEnabled.value) {
-    resumeAutoRefresh()
     resumeCountdown()
   }
 })
@@ -697,7 +701,6 @@ async function loadThresholds() {
 onUnmounted(() => {
   window.removeEventListener('keydown', handleKeydown)
   abortDashboardFetch()
-  pauseAutoRefresh()
   pauseCountdown()
 })
 
@@ -705,10 +708,8 @@ onUnmounted(() => {
 watch(autoRefreshEnabled, (enabled) => {
   if (enabled) {
     autoRefreshCountdown.value = Math.floor(autoRefreshIntervalMs.value / 1000)
-    resumeAutoRefresh()
     resumeCountdown()
   } else {
-    pauseAutoRefresh()
     pauseCountdown()
     autoRefreshCountdown.value = 0
   }