优化后端构建方式，修改首页报表 bug

dashboard/frontend/src/views/home/index.vue

@@ -173,12 +173,7 @@ watch(deviceDays, () => {
 // ===== 设备日活趋势 =====
 const activeDays = ref(30);
 const activeLoading = ref(false);
-const activeLatest = ref({ date: '', total: 0 });
-
-const activeLatestLabel = computed(() => {
-  if (activeDays.value === 1) return `${activeLatest.value.date} 总活跃`;
-  return `${activeLatest.value.date.slice(5)} 总日活`;
-});
+const activeTodayTotal = ref(0);
 
 function buildActiveChartOptions(dates: string[], series: Array<{ name: string; data: number[] }>): ECOption {
   const isHourly = activeDays.value === 1;
@@ -257,7 +252,13 @@ async function loadActiveDaily() {
   activeLoading.value = true;
   const { data, error } = await fetchGetActiveDaily(activeDays.value);
   if (!error && data) {
-    activeLatest.value = data.latest;
+    // 今天模式（按小时）：累加所有小时；多天模式：取末尾（今天）
+    const isHourly = activeDays.value === 1;
+    const lastIdx = (data.dates?.length || 1) - 1;
+    activeTodayTotal.value = (data.series || []).reduce((sum: number, s: { data: number[] }) => {
+      if (isHourly) return sum + s.data.reduce((a: number, b: number) => a + b, 0);
+      return sum + (s.data[lastIdx] || 0);
+    }, 0);
     lastActiveData.value = { dates: data.dates, series: data.series };
     await updateActiveChart(() => buildActiveChartOptions(data.dates, data.series));
   }
@@ -359,7 +360,7 @@ onMounted(() => {
           <template #header>活跃趋势</template>
           <template #header-extra>
             <NSpace align="center" :size="12">
-              <NTag type="success" size="small">{{ activeLatestLabel }} {{ activeLatest.total }}</NTag>
+              <NTag type="success" size="small">今日日活 {{ activeTodayTotal }}</NTag>
               <NRadioGroup v-model:value="activeDays" size="small">
                 <NRadioButton :value="1">今天</NRadioButton>
                 <NRadioButton :value="7">近7天</NRadioButton>