重构 monorepo 并完善网页端订阅与首页体验

- 迁移为 frontend-web、frontend-electron、backend-web 与 docker 部署结构
- 网页端：订阅门禁二次弹窗、套餐/支付组件化、顶栏分组对齐
- 首页：最近文件与模板库布局优化，缩略图对齐，下载与删除操作
- 新增管理后台、支付与云端文件 API，更新 README 与项目规范

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

frontend-electron/vendor/layui/css/modules/code.css

@@ -0,0 +1,29 @@
+/**
+ 
+ @Name: layui.code
+ @Description：Classic modular front-end UI framework
+ @License：MIT
+ 
+ */
+
+/* 加载就绪标志 */
+html #layuicss-skincodecss{display:none; position: absolute; width:1989px;}
+
+/* 默认风格 */
+.layui-code-view{display: block; position: relative; margin: 10px 0; padding: 0; border: 1px solid #eee; border-left-width: 6px; background-color: #FAFAFA; color: #333; font-family: Courier New; font-size: 12px;}
+.layui-code-h3{position: relative; padding: 0 10px; height: 40px; line-height: 40px; border-bottom: 1px solid #eee; font-size: 12px;}
+.layui-code-h3 a{position: absolute; right: 10px; top: 0; color: #999;}
+.layui-code-view .layui-code-ol{position: relative; overflow: auto;}
+.layui-code-view .layui-code-ol li{position: relative; margin-left: 45px; line-height: 20px; padding: 0 10px; border-left: 1px solid #e2e2e2; list-style-type: decimal-leading-zero; *list-style-type: decimal; background-color: #fff;}
+.layui-code-view .layui-code-ol li:first-child{padding-top: 10px;}
+.layui-code-view .layui-code-ol li:last-child{padding-bottom: 10px;}
+.layui-code-view pre{margin: 0;}
+
+/* notepadd++风格 */
+.layui-code-notepad{border: 1px solid #0C0C0C; border-left-color: #3F3F3F; background-color: #0C0C0C; color: #C2BE9E}
+.layui-code-notepad .layui-code-h3{border-bottom: none;}
+.layui-code-notepad .layui-code-ol li{background-color: #3F3F3F; border-left: none;}
+
+/* 代码预览 */
+.layui-code-demo .layui-code{visibility: visible !important; margin: -15px; border-top: none; border-right: none; border-bottom: none;}
+.layui-code-demo .layui-tab-content{padding: 15px; border-top: none}