永久会员与模板库后台化：预览门控、轻量首页与 Admin CRUD

- 会员改为永久激活方案；云端文件不再拦截非会员；预览弹窗内导出/打印才校验
- 首页最近文件支持本地记录，登录后与云端合并；移除独立会员页与订阅页
- 模板库入库管理：soon_templates 表、Admin 上传 CRUD、/templates 轻量列表与按需下载

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-web/js/common/portal-auth.js

@@ -24,7 +24,6 @@
     var tok = localStorage.getItem('soon_access') || '';
     var login = document.getElementById('auth_login');
     var reg = document.getElementById('auth_register');
-    var member = document.getElementById('auth_member');
     var admin = document.getElementById('auth_admin');
     var logout = document.getElementById('auth_logout');
     var avatar = document.getElementById('auth_avatar');
@@ -34,7 +33,6 @@
     showAuthedNav();
     if (login) login.style.display = 'none';
     if (reg) reg.style.display = 'none';
-    if (member) member.style.display = 'inline-flex';
     if (logout) logout.style.display = 'inline-flex';
 
     var base = (window.SOON_DEPLOY_CONFIG && window.SOON_DEPLOY_CONFIG.api_v1_base) || '';