feat(i18n): ServerManager 服务器管理页国际化 — 27 处硬编码中文改翻译键 + server 命名空间(48 键)

- ServerManager.tsx: 页面标题/按钮/搜索/状态筛选/表头/分页/toast/CSV导出/确认弹框 全量 t() 化
- 复用 common.* 通用键(refresh/export/delete/status/actions/loading/running/stopped/maintenance/offline)
- 新增 server.* 命名空间: title/subtitle/batchImport/cloudImport/csvImport/addServer/searchPlaceholder/tableHeaders/pagination/toast/csv 子组
- zh-CN/en-US 键总数 242→290 (server 48 键, 中英完全对齐)
- tsc -b=0, npm build=✓(19.13s), 17/17 集成测试通过

frontend/src/locales/zh-CN.json

@@ -269,5 +269,53 @@
       "memory": "内存",
       "disk": "磁盘"
     }
+  },
+  "server": {
+    "title": "服务器管理",
+    "subtitle": "管理云平台服务器资产",
+    "batchImport": "批量导入",
+    "importMethod": "选择导入方式",
+    "cloudImport": "云主机导入",
+    "cloudImportHint": "从云平台同步",
+    "csvImport": "CSV导入",
+    "csvImportHint": "hostname + IP 即可",
+    "addServer": "添加服务器",
+    "searchPlaceholder": "搜索主机名或IP...",
+    "allStatus": "全部状态",
+    "hostname": "主机名",
+    "ipAddress": "IP地址",
+    "publicIp": "公网IP",
+    "config": "配置",
+    "usage": "使用率",
+    "tags": "标签",
+    "noData": "暂无服务器数据",
+    "selected": "已选择 {{count}} 项",
+    "batchDelete": "批量删除",
+    "perPage": "每页",
+    "items": "条",
+    "totalItems": "共 {{count}} 条",
+    "deleteTitle": "删除服务器",
+    "deleted": "服务器已删除",
+    "batchDeleteTitle": "批量删除服务器",
+    "updated": "服务器已更新",
+    "created": "服务器已创建",
+    "saveFailed": "保存失败，请重试",
+    "noExportData": "没有可导出的数据",
+    "exported": "已导出 {{count}} 台服务器",
+    "deletedCount": "已删除 {{count}} 台服务器",
+    "deleteFailed": "删除失败",
+    "batchDeleteFailed": "批量删除失败",
+    "csv": {
+      "hostname": "主机名",
+      "ip": "IP地址",
+      "publicIp": "公网IP",
+      "port": "端口",
+      "os": "操作系统",
+      "cpu": "CPU(核)",
+      "memory": "内存(GB)",
+      "disk": "磁盘(GB)",
+      "status": "状态",
+      "tags": "标签"
+    }
   }
 }