chore: 默认品牌名从'微授权'改为'网络验证'

Co-Authored-By: Claude <noreply@anthropic.com>

backend/cmd/main.go

@@ -329,7 +329,7 @@ func serveIndexHTML(c *gin.Context, indexHTML string) {
 		settings = make(map[string]interface{})
 	}
 
-	siteName := getSettingString(settings, "site_name", "微授权")
+	siteName := getSettingString(settings, "site_name", "网络验证")
 	siteDescription := getSettingString(settings, "site_description", "专业的应用验证平台")
 	siteLogo := getSettingString(settings, "site_logo", "")
 	siteFavicon := getSettingString(settings, "site_favicon", "")