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/overlay-primitives.css

@@ -2,7 +2,7 @@
  * AKSRT Overlay / Glass Primitives
  *
  * Provides backdrop-filter glass surfaces used by header, footer-tabbar,
- * floating buttons and search overlays — matching zibll's blur system.
+ * floating buttons and search overlays — matching legacy's blur system.
  *
  * @package AKSRT
  */
@@ -19,7 +19,7 @@
 
 /* ============================================================
  * Glass on site-nav (when using fixed/sticky mode)
- * Applied via .site-nav--blur already; this adds the zibll-grade
+ * Applied via .site-nav--blur already; this adds the legacy-grade
  * saturate(5) blur(20px) instead of the lighter saturate(1.5) blur(18px).
  * ============================================================ */
 .site-nav--glass {
@@ -41,7 +41,7 @@ html.dark .site-nav--glass.is-scrolled {
 
 /* ============================================================
  * Glass on footer-tabbar (already uses backdrop-filter in footer.css;
- * this class can be toggled to match zibll's exact blur spec)
+ * this class can be toggled to match legacy's exact blur spec)
  * ============================================================ */
 .footer-tabbar--glass {
   -webkit-backdrop-filter: saturate(5) blur(20px);
@@ -66,7 +66,7 @@ html.dark .footer-tabbar--glass {
 }
 
 /* ============================================================
- * Scroll shadow on glass header (zibll: .body-scroll .header)
+ * Scroll shadow on glass header (legacy: .body-scroll .header)
  * ============================================================ */
 body.has-scrolled .site-nav--glass {
   box-shadow: 0 4px 10px rgba(20, 28, 48, 0.06);