Refactor code and fix linter warnings (#3627)

* refactor: use any instead of empty interface

* refactor: code cleanup

sub/subJsonService.go

@@ -4,6 +4,7 @@ import (
 	_ "embed"
 	"encoding/json"
 	"fmt"
+	"maps"
 	"strings"
 
 	"github.com/mhsanaei/3x-ui/v2/database/model"
@@ -197,9 +198,8 @@ func (s *SubJsonService) getConfig(inbound *model.Inbound, client model.Client,
 
 		newOutbounds = append(newOutbounds, s.defaultOutbounds...)
 		newConfigJson := make(map[string]any)
-		for key, value := range s.configJson {
-			newConfigJson[key] = value
-		}
+		maps.Copy(newConfigJson, s.configJson)
+
 		newConfigJson["outbounds"] = newOutbounds
 		newConfigJson["remarks"] = s.SubService.genRemark(inbound, client.Email, extPrxy["remark"].(string))
 

sub/subService.go

@@ -484,8 +484,8 @@ func (s *SubService) genVlessLink(inbound *model.Inbound, email string) string {
 	externalProxies, _ := stream["externalProxy"].([]any)
 
 	if len(externalProxies) > 0 {
-		links := ""
-		for index, externalProxy := range externalProxies {
+		links := make([]string, 0, len(externalProxies))
+		for _, externalProxy := range externalProxies {
 			ep, _ := externalProxy.(map[string]any)
 			newSecurity, _ := ep["forceTls"].(string)
 			dest, _ := ep["dest"].(string)
@@ -511,12 +511,9 @@ func (s *SubService) genVlessLink(inbound *model.Inbound, email string) string {
 
 			url.Fragment = s.genRemark(inbound, email, ep["remark"].(string))
 
-			if index > 0 {
-				links += "\n"
-			}
-			links += url.String()
+			links = append(links, url.String())
 		}
-		return links
+		return strings.Join(links, "\n")
 	}
 
 	link := fmt.Sprintf("vless://%s@%s:%d", uuid, address, port)