Bind Feishu identity to OpenVPN sessions and refine management UI

frontend/src/locales/en-US.json

@@ -531,6 +531,7 @@
     "connectedDuration": "Duration",
     "kickOffline": "Kick",
     "noOnlineUsers": "No online users",
+    "identityUnknown": "Identity unknown",
     "trafficAlert": "⚠ Abnormal Traffic Alert",
     "userTunnel": "User/Tunnel",
     "alertType": "Type",

frontend/src/locales/zh-CN.json

@@ -531,6 +531,7 @@
     "connectedDuration": "已连接时长",
     "kickOffline": "踢下线",
     "noOnlineUsers": "当前无在线用户",
+    "identityUnknown": "身份未识别",
     "trafficAlert": "⚠ 异常流量告警",
     "userTunnel": "用户/隧道",
     "alertType": "类型",