fix: 修正订阅转换URL构建逻辑，确保token和sub参数正确拼接

Author: cmliu

_worker.js

@@ -277,7 +277,7 @@ export default {
                             }
                         }
                     } else { // 订阅转换
-                        const 订阅转换URL = `${config_JSON.订阅转换配置.SUBAPI}/sub?target=${订阅类型}&url=${encodeURIComponent(url.protocol + '//' + url.host + '/sub?target=mixed&token=' + 订阅TOKEN) + (url.searchParams.has('sub') && url.searchParams.get('sub') != '' ? `&sub=${url.searchParams.get('sub')}` : '')}&config=${encodeURIComponent(config_JSON.订阅转换配置.SUBCONFIG)}&emoji=${config_JSON.订阅转换配置.SUBEMOJI}&scv=${config_JSON.跳过证书验证}`;
+                        const 订阅转换URL = `${config_JSON.订阅转换配置.SUBAPI}/sub?target=${订阅类型}&url=${encodeURIComponent(url.protocol + '//' + url.host + '/sub?target=mixed&token=' + 订阅TOKEN + (url.searchParams.has('sub') && url.searchParams.get('sub') != '' ? `&sub=${url.searchParams.get('sub')}` : ''))}&config=${encodeURIComponent(config_JSON.订阅转换配置.SUBCONFIG)}&emoji=${config_JSON.订阅转换配置.SUBEMOJI}&scv=${config_JSON.跳过证书验证}`;
                         try {
                             const response = await fetch(订阅转换URL, { headers: { 'User-Agent': 'Subconverter for ' + 订阅类型 + ' edge' + 'tunnel(https://github.com/cmliu/edge' + 'tunnel)' } });
                             if (response.ok) {