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/breadcrumb.css

@@ -1,4 +1,4 @@
-/* ========== 面包屑导航 — 对齐 zibll .breadcrumb (main.css) ========== */
+/* ========== 面包屑导航 — 对齐 legacy .breadcrumb (main.css) ========== */
 /* Single source for breadcrumb chrome. Do not re-define in layout.css. */
 
 .breadcrumb,
@@ -24,7 +24,7 @@ ul.breadcrumb,
   display: block;
 }
 
-/* Zibll uses flat li + li:before separators (not flex-gap nodes) */
+/* legacy uses flat li + li:before separators (not flex-gap nodes) */
 .breadcrumb > li,
 ul.breadcrumb > li,
 .breadcrumb-nav li,
@@ -69,7 +69,7 @@ ul.breadcrumb > li:last-child,
   color: var(--main-color, var(--color-ink-2, #4e5358));
 }
 
-/* Cover / video footer breadcrumb — Zibll single-cover-con / single-video */
+/* Cover / video footer breadcrumb — legacy single-cover-con / single-video */
 .single-cover-con .breadcrumb,
 .single-cover-con ul.breadcrumb,
 .single-cover-con .breadcrumb-nav,