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>

backend-web/public/admin.php

@@ -9,6 +9,7 @@ use Soon\Api\Admin\Controllers\PaymentController;
 use Soon\Api\Admin\Controllers\PlansController;
 use Soon\Api\Admin\Controllers\SettingsController;
 use Soon\Api\Admin\Controllers\StatsController;
+use Soon\Api\Admin\Controllers\TemplatesController;
 use Soon\Api\Admin\Controllers\UsersController;
 use Soon\Api\Core\Config;
 use Soon\Api\Core\Json;
@@ -58,6 +59,11 @@ Router::post('/api/admin/orders/{id}/refund/reject', [OrdersController::class, '
 Router::get('/api/admin/plans', [PlansController::class, 'list']);
 Router::post('/api/admin/plans', [PlansController::class, 'upsert']);
 
+Router::get('/api/admin/templates', [TemplatesController::class, 'list']);
+Router::post('/api/admin/templates', [TemplatesController::class, 'create']);
+Router::put('/api/admin/templates/{id}', [TemplatesController::class, 'update']);
+Router::delete('/api/admin/templates/{id}', [TemplatesController::class, 'delete']);
+
 Router::get('/api/admin/settings', [SettingsController::class, 'list']);
 Router::post('/api/admin/settings', [SettingsController::class, 'set']);
 Router::post('/api/admin/settings/batch', [SettingsController::class, 'setBatch']);