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

pkg/protocol/agent.go

@@ -138,6 +138,7 @@ type NodeAccessLog struct {
 	RemoteAddr    string `json:"remote_addr"`
 	Host          string `json:"host"`
 	Path          string `json:"path"`
+	UserAgent     string `json:"user_agent,omitempty"`
 	StatusCode    int    `json:"status_code"`
 	BytesSent     int64  `json:"bytes_sent"`      // body bytes = 已提供数据
 	RequestLength int64  `json:"request_length"`  // 接收数据

pkg/render/openresty/types.go

@@ -60,7 +60,7 @@ http {
     fastcgi_temp_path __OPENFLARE_NGINX_CACHE_DIR__/fastcgi_temp;
     uwsgi_temp_path __OPENFLARE_NGINX_CACHE_DIR__/uwsgi_temp;
     scgi_temp_path __OPENFLARE_NGINX_CACHE_DIR__/scgi_temp;
-{{OpenRestyConnectionUpgradeMap}}{{OpenRestyDefaultServerBlock}}    log_format openflare_json escape=json '{"ts":"$time_iso8601","host":"$host","path":"$request_uri","remote_addr":"$remote_addr","status":$status,"request_time":$request_time,"bytes_sent":$body_bytes_sent,"request_length":$request_length}';
+{{OpenRestyConnectionUpgradeMap}}{{OpenRestyDefaultServerBlock}}    log_format openflare_json escape=json '{"ts":"$time_iso8601","host":"$host","path":"$request_uri","remote_addr":"$remote_addr","status":$status,"request_time":$request_time,"bytes_sent":$body_bytes_sent,"request_length":$request_length,"user_agent":"$http_user_agent"}';
     access_log {{OpenRestyAccessLogPath}} openflare_json;
     sendfile on;
     tcp_nopush on;