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/homepage-fixed/base-1.css

@@ -1,11 +1,11 @@
 /**
- * Homepage Fixed Layout — Zibll Visual Parity
+ * Homepage Fixed Layout — legacy Visual Parity
  *
- * Implements Zibll's homepage visual language:
+ * Implements legacy's homepage visual language:
  * - System font stack with Chinese fallbacks
  * - 1200px container, 311px sidebar
  * - Post cards: list mode (190px thumb) + card mode (3-col grid)
- * - Zibll shadow/radius/spacing values
+ * - legacy shadow/radius/spacing values
  * - scale(1.02) thumbnail hover
  * - Lazy-load animations (blur/fade/scale)
  * - Full responsive: 1200/991/767/640px breakpoints
@@ -32,7 +32,7 @@
   background: transparent;
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
-  /* Slightly looser than stock zibll short pages: air between stream and footer */
+  /* Slightly looser than stock legacy short pages: air between stream and footer */
   padding-bottom: 28px;
 }