fix(watch): 指标进度条 ≥80% 变红，到期倒计时归零加固

进度条阈值由 70/90 改为 80% 红色；remaining_sec≤0 时立即 refreshPins。

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/changelog/2026-06-12-watch-slot-ttl-metrics-ui.md

@@ -41,3 +41,7 @@ bash scripts/local_verify.sh
 ```
 
 浏览器：监测槽选 30 分默认、切换时长、进度条与负载 chip 显示正常。
+
+## 补充（进度条阈值）
+
+- CPU/内存/硬盘进度条：**≥80% 变红**，低于 80% 为绿色（`WatchMetricBar.vue`）。

frontend/src/components/watch/WatchMetricBar.vue

@@ -5,8 +5,7 @@ const props = defineProps<{
 }>()
 
 function barColor(v: number): string {
-  if (v >= 90) return 'error'
-  if (v >= 70) return 'warning'
+  if (v >= 80) return 'error'
   return 'success'
 }
 

frontend/src/composables/useWatchPins.ts

@@ -85,11 +85,14 @@ function tickCountdown() {
   let shouldRefresh = false
   for (const slot of slots.value) {
     if (slot.empty || slot.monitoring_enabled === false) continue
-    if (slot.remaining_sec != null && slot.remaining_sec > 0) {
-      slot.remaining_sec -= 1
-      if (slot.remaining_sec <= 0) {
-        shouldRefresh = true
-      }
+    if (slot.remaining_sec == null) continue
+    if (slot.remaining_sec <= 0) {
+      shouldRefresh = true
+      continue
+    }
+    slot.remaining_sec -= 1
+    if (slot.remaining_sec <= 0) {
+      shouldRefresh = true
     }
   }
   if (shouldRefresh) {