refactor: update go backend with cli and config

backend/main.go

@@ -2,11 +2,21 @@
 package main
 
 import (
+	"log"
 	"net/http"
+
 	"github.com/gin-gonic/gin"
 )
 
 func main() {
+	args := ParseCLI()
+
+	cfg, err := LoadConfig(args.Config)
+	if err != nil {
+		log.Fatal(err)
+	}
+	_ = cfg
+
 	// 创建默认的 Gin 引擎(包含 Logger 和 Recovery 中间件)
 	r := gin.Default()