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)

inc/helpers/menu-decoration.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Menu decoration helpers — Zibll's zib_menu_options contract.
+ * Menu decoration helpers — legacy's aksrt_menu_options contract.
  *
  * @package AKSRT
  */
@@ -8,7 +8,7 @@
 defined('ABSPATH') || exit;
 
 /**
- * Read one menu item option from post meta zib_menu_options.
+ * Read one menu item option from post meta aksrt_menu_options.
  *
  * @param int    $id      Menu item ID.
  * @param string $key     Option key.
@@ -18,7 +18,7 @@ defined('ABSPATH') || exit;
 function aksrt_menu_pz(int $id, string $key = '', $default = '') {
 	static $options = [];
 	if (!isset($options[$id])) {
-		$raw = get_post_meta($id, 'zib_menu_options', true);
+		$raw = get_post_meta($id, 'aksrt_menu_options', true);
 		$options[$id] = is_array($raw) ? $raw : [];
 	}
 	if ($key === '') {
@@ -52,7 +52,7 @@ function aksrt_render_menu_icon(string $icon_class, bool $enabled = true): strin
 	if (!$enabled || $icon_class === '') {
 		return '';
 	}
-	// Zibll uses the Font Awesome 5 `fa` prefix.
+	// legacy uses the Font Awesome 5 `fa` prefix.
 	if (strpos($icon_class, 'fa') === false) {
 		$icon_class = 'fa fas fa-' . ltrim($icon_class, '-');
 	} elseif (strpos($icon_class, 'fa-') === 0 && strpos($icon_class, ' ') === false) {