feat: 新增会话ID伪装功能，优化日志系统

- 新增 session_id_masking_enabled 配置，启用后将在15分钟内固定
  metadata.user_id 中的 session ID
- TLS fingerprint 模块日志从自定义 debugLog 迁移到 slog
- main.go 添加 slog 初始化，根据 gin mode 设置日志级别
- 前端创建/编辑账号模态框添加会话ID伪装开关
- 多语言支持（中英文）

backend/cmd/server/main.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"flag"
 	"log"
+	"log/slog"
 	"net/http"
 	"os"
 	"os/signal"
@@ -44,7 +45,25 @@ func init() {
 	}
 }
 
+// initLogger configures the default slog handler based on gin.Mode().
+// In non-release mode, Debug level logs are enabled.
+func initLogger() {
+	var level slog.Level
+	if gin.Mode() == gin.ReleaseMode {
+		level = slog.LevelInfo
+	} else {
+		level = slog.LevelDebug
+	}
+	handler := slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
+		Level: level,
+	})
+	slog.SetDefault(slog.New(handler))
+}
+
 func main() {
+	// Initialize slog logger based on gin mode
+	initLogger()
+
 	// Parse command line flags
 	setupMode := flag.Bool("setup", false, "Run setup wizard in CLI mode")
 	showVersion := flag.Bool("version", false, "Show version information")