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/pages/admin/assets/js/views/dashboard.js

@@ -33,6 +33,7 @@
       { href: '#/users', label: '用户管理' },
       { href: '#/orders', label: '订单管理' },
       { href: '#/plans', label: '套餐配置' },
+      { href: '#/templates', label: '模板库' },
       { href: '#/payment', label: '支付密钥' },
       { href: '#/settings', label: '系统设置' },
       { href: '#/audits', label: '审计日志' },
@@ -96,7 +97,7 @@
       statCard('订单总数', d.orders, { href: '#/orders', hint: '含全部状态' }) +
       statCard('今日订单', d.orders_today, { href: '#/orders', hint: '按创建日统计' }) +
       statCard('待支付', d.orders_pending || 0, { href: '#/orders?status=pending', hint: '需关注超时未付' }) +
-      statCard('活跃订阅', d.active_subscriptions, { href: '#/users', hint: '有效会员数' }) +
+      statCard('活跃会员', d.active_subscriptions, { href: '#/users', hint: '有效会员数' }) +
       statCard('今日收入', I().formatCents(d.revenue_today_cents), { href: '#/orders', hint: '已支付订单' }) +
       statCard('云端文件', d.files_total, { hint: '未删除的设计文件' }) +
       statCard('退款待审', d.refunds_pending || 0, { href: '#/orders?refund_status=pending', hint: '需在订单页处理' });