feat(access-logs): 接入 User-Agent 与设备/浏览器/状态码分布

- Agent 访问日志上报 user_agent，OpenResty log_format 输出 http_user_agent
- of_node_access_logs 新增 user_agent 列并写入 ClickHouse
- 访问日志概览新增：设备类型饼图、状态码饼图、浏览器/OS/User-Agent 排行
- 日志明细列表增加 User-Agent 列
- 扩展 UA 解析工具（browser/os/device）并支持 CLI 识别

internal/model/analytics/node_access_log.go

@@ -10,7 +10,7 @@ import (
 
 const (
 	nodeAccessLogTableName     = "of_node_access_logs"
-	nodeAccessLogInsertColumns = "id, node_id, logged_at, remote_addr, region, host, path, status_code, bytes_sent, request_length, request_time_ms, created_at"
+	nodeAccessLogInsertColumns = "id, node_id, logged_at, remote_addr, region, host, path, user_agent, status_code, bytes_sent, request_length, request_time_ms, created_at"
 )
 
 // NodeAccessLog stores OpenFlare edge node access records in ClickHouse.
@@ -22,6 +22,7 @@ type NodeAccessLog struct {
 	Region        string    `gorm:"column:region"`
 	Host          string    `gorm:"column:host"`
 	Path          string    `gorm:"column:path"`
+	UserAgent     string    `gorm:"column:user_agent"`
 	StatusCode    int32     `gorm:"column:status_code"`
 	BytesSent     uint64    `gorm:"column:bytes_sent"`
 	RequestLength uint64    `gorm:"column:request_length"`