feat(i18n): Dashboard 页面内容国际化迁移 — 3 组件(Dashboard/DashboardCharts/DashboardRecent)硬编码中文改翻译键 + zh-CN/en-US 新增 dashboard.* 121 键(241 total)

- Dashboard.tsx: 标题/副标题/刷新/服务器按钮/StatStrip 7 标签/概览卡片标题 全部 t() 化
- DashboardCharts.tsx: 云成本概览/Top5资源使用/费用分布/月度趋势/环比标签 i18n(computeMonthChange 用 i18n.t 避开非组件上下文)
- DashboardRecent.tsx: 告警消息/证书到期/发布历史/服务器状态/集群状态 5 卡片全量 i18n
- zh-CN.json/en-US.json: dashboard 命名空间扩展 stat/alerts/certificates/releases/serversStatus/clusters/cost/topUsage/system 9 子分组
- 翻译键总数 120→241 (zh-CN/en-US 完全对齐)
- tsc -b=0, npm build=✓(19.01s), 17/17 集成测试通过, Docker healthy

frontend/src/locales/zh-CN.json

@@ -179,20 +179,95 @@
   },
   "dashboard": {
     "title": "仪表盘",
-    "serverStats": "服务器统计",
-    "totalServers": "服务器总数",
-    "onlineServers": "在线服务器",
-    "k8sClusters": "K8s集群",
-    "runningPods": "运行中Pod",
-    "todayAlerts": "今日告警",
-    "recentAlerts": "最近告警",
-    "recentPipelines": "最近流水线",
-    "recentReleases": "最近发布",
-    "systemOverview": "系统概览",
-    "resourceUsage": "资源使用率",
-    "cpuUsage": "CPU使用率",
-    "memoryUsage": "内存使用率",
-    "diskUsage": "磁盘使用率",
-    "quickActions": "快捷操作"
+    "subtitle": "实时监控和运维概览",
+    "lastUpdated": "最后更新",
+    "refresh": "刷新",
+    "refreshing": "刷新中",
+    "servers": "服务器",
+    "stat": {
+      "servers": "服务器",
+      "running": "运行中",
+      "k8sClusters": "K8s 集群",
+      "healthyClusters": "健康集群",
+      "alerts": "告警",
+      "critical": "严重",
+      "monthlyCost": "本月成本"
+    },
+    "alerts": {
+      "title": "告警消息",
+      "description": "最近触发的告警事件",
+      "viewAll": "查看全部",
+      "empty": "暂无告警事件",
+      "emptyHint": "所有系统运行正常"
+    },
+    "certificates": {
+      "title": "证书到期提醒",
+      "description": "SSL证书到期时间监控",
+      "expiringSoon": "即将过期",
+      "expiringIn30Days": "30天内过期",
+      "empty": "暂无证书数据",
+      "expireDate": "到期",
+      "expired": "已过期",
+      "days": "天"
+    },
+    "releases": {
+      "title": "发布历史",
+      "description": "今日应用发布记录",
+      "viewAll": "查看全部",
+      "empty": "暂无发布记录",
+      "success": "成功",
+      "failed": "失败",
+      "deploying": "发布中",
+      "rolledBack": "已回滚",
+      "building": "构建中"
+    },
+    "serversStatus": {
+      "title": "服务器状态",
+      "description": "服务器运行状态分布",
+      "viewAll": "查看全部",
+      "running": "运行中",
+      "maintenance": "维护中",
+      "stopped": "已停止",
+      "cpu": "CPU",
+      "memory": "内存",
+      "empty": "暂无服务器"
+    },
+    "clusters": {
+      "title": "Kubernetes 集群",
+      "description": "Kubernetes集群健康状态",
+      "viewAll": "查看全部",
+      "empty": "暂无集群数据",
+      "healthy": "健康",
+      "warning": "警告",
+      "error": "异常",
+      "nodes": "节点",
+      "pods": "Pod",
+      "cpu": "CPU",
+      "memory": "内存"
+    },
+    "cost": {
+      "title": "云成本概览",
+      "description": "本月各云平台费用支出",
+      "distribution": "费用分布",
+      "monthlyTrend": "月度趋势",
+      "noData": "暂无数据",
+      "newCost": "新增费用",
+      "flat": "持平",
+      "vsLastMonth": "较上月"
+    },
+    "topUsage": {
+      "title": "Top5 资源使用",
+      "description": "CPU、内存、磁盘使用率最高",
+      "cpu": "CPU",
+      "memory": "内存",
+      "disk": "磁盘"
+    },
+    "resourceUsage": {
+      "title": "资源使用率趋势",
+      "description": "过去24小时系统资源使用情况",
+      "cpu": "CPU",
+      "memory": "内存",
+      "disk": "磁盘"
+    }
   }
 }