refactor(assets): vendor 资产迁入标准目录并全仓去除 zibll 标识

- assets/vendor 全量迁移: fontawesome5→assets/fontawesome5, css→assets/css,
  js→assets/js/runtime(避开 14 个同名自有文件), img 合并去重→assets/img,
  fonts→assets/fonts; 删除 assets/vendor
- libs 五个与 widgets/third-party 字节相同的库不重复入库, loader paths 改指向
- 运行时切换: _win.uri=assets 根, loader baseUrl=/js/runtime, enlighter 注入
  路径同步; PHP 7 个引用文件切换并改名 $zibll_*→$runtime_*
- 去品牌: Qinver 头注释/品牌 console.log/演示链接清除, 默认文案中性化
- 功能标识符改名: zib__→aksrt__, zib_ajax→aksrt_ajax, window.zib→
  window.aksrtLegacy, zibllblock/*→aksrtblock/*, .zib-widget→.aksrt-panel,
  .zib-slider→.aksrt-slider, zib_menu_options meta 键等
- 自有 CSS 改名: legacy-utilities/compat-vars/footer shell
- admin SPA 重建; 契约测试同步(路径/断言/文件更名)
- 例外保留: tests/visual 对照环境与 fixtures 前缀(外部 Zibll 产品引用)

验证: php -l 133 个改动文件通过; runtime 86 个 JS node --check 通过;
契约测试 68/70(2 个失败经 stash 对照确认为存量问题)

assets/css/frontend/single-post/shell.css

@@ -1,5 +1,5 @@
 /* Single page shell — relies on body.site-layout-1/2/3 float dual-column
- * defined in layout.css (Zibll 1:1). Page-owned overrides stay minimal. */
+ * defined in layout.css (legacy 1:1). Page-owned overrides stay minimal. */
 
 /* Single article stack lives inside .content-layout as direct children;
  * do not re-enable the legacy primary/aside grid here. */
@@ -25,13 +25,13 @@ body.single main.container .content-layout > .breadcrumbs-wrap {
   padding-top: 2px;
 }
 
-/* Sticky TOC widget in sidebar — parent .sidebar is position:unset like Zibll */
+/* Sticky TOC widget in sidebar — parent .sidebar is position:unset like legacy */
 body.single .sidebar .posts-nav-box.toc-widget {
   position: sticky;
   top: calc(var(--nav-height, 60px) + 16px);
 }
 
-body.single .sidebar .zib-widget,
+body.single .sidebar .aksrt-panel,
 body.single .sidebar .widget {
   margin-bottom: 15px;
 }