fix: 批量安装按钮检测 + 审计日志中文化 + terminal断开反馈

1. updateBatchBar() hasAgent 判断从 agent_api_key_set 改为 agent_version
2. 所有后端 AuditLog detail 字段统一中文
3. audit.html 操作/目标类型中文映射
4. terminal.html 断开覆盖层 + 重新连接按钮
5. Agent os_release 上报 + 前端系统版本拆分

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

server/api/webssh.py

@@ -136,7 +136,7 @@ async def terminal_ws(
             action="webssh_connect",
             target_type="server",
             target_id=server.id,
-            detail=f"WebSSH to {server.name} ({server.domain})",
+            detail=f"WebSSH 连接 {server.name} ({server.domain})",
             ip_address=client_ip,
         ))
 
@@ -344,7 +344,7 @@ async def terminal_ws(
                     action="webssh_disconnect",
                     target_type="server",
                     target_id=server.id,
-                    detail=f"WebSSH disconnected from {server.name}",
+                    detail=f"WebSSH 断开 {server.name}",
                     ip_address=client_ip,
                 ))
         except Exception: