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/assets/css/subscribe-gate.css

@@ -222,3 +222,86 @@
   opacity: 0.45;
   cursor: not-allowed;
 }
+
+.soon-login-gate__form {
+  padding: 0 24px 8px;
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+
+.soon-login-gate__form .soon-input-wrap {
+  width: 100%;
+}
+
+.soon-login-gate__error {
+  color: #f87171;
+  font-size: 13px;
+  margin: 0;
+}
+
+.soon-login-gate__links {
+  padding: 0 24px 16px;
+  font-size: 13px;
+  color: rgba(255, 255, 255, 0.65);
+}
+
+.soon-login-gate__links a {
+  color: #7dd3fc;
+}
+
+.soon-activate-price {
+  padding: 16px 20px;
+  border-radius: 12px;
+  background: rgba(255, 255, 255, 0.04);
+  border: 1px solid rgba(255, 255, 255, 0.08);
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
+.soon-activate-price__label {
+  font-size: 13px;
+  color: rgba(255, 255, 255, 0.55);
+}
+
+.soon-activate-price__value {
+  font-size: 28px;
+  font-weight: 700;
+  color: #fff;
+}
+
+.soon-activate-price__hint {
+  font-size: 12px;
+  color: rgba(255, 255, 255, 0.5);
+}
+
+.soon-activate-channels {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 10px;
+  margin-top: 16px;
+}
+
+.soon-activate-channel {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  padding: 8px 14px;
+  border-radius: 999px;
+  border: 1px solid rgba(255, 255, 255, 0.12);
+  font-size: 13px;
+  cursor: pointer;
+}
+
+.soon-activate-channel.is-active {
+  border-color: #38bdf8;
+  background: rgba(56, 189, 248, 0.12);
+}
+
+.soon-activate-load {
+  margin: 12px 0 0;
+  font-size: 13px;
+  color: rgba(255, 255, 255, 0.55);
+  min-height: 18px;
+}