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/aksrt-single.php

@@ -1,6 +1,6 @@
 <?php
 /**
- * Unified single post composition (Zibll-style closed surface).
+ * Unified single post composition (legacy-style closed surface).
  *
  * single.php stays a thin shell. All article assembly lives here.
  *
@@ -33,7 +33,7 @@ if (!function_exists('aksrt_single_build_context')) :
 			? aksrt_reading_minutes($post_id)
 			: 0;
 
-		// Zibll primary meta = comment/views/likes via meta_box_html.
+		// legacy primary meta = comment/views/likes via meta_box_html.
 		$meta_items = [];
 		$meta_box_html = function_exists('aksrt_get_single_meta_box')
 			? aksrt_get_single_meta_box('abs-right', 'down', $post_id)
@@ -63,7 +63,7 @@ if (!function_exists('aksrt_single_build_context')) :
 		$paid_settings = class_exists('\AKSRT\Settings\Settings') ? \AKSRT\Settings\Settings::get_paid_content_settings() : [];
 		$paid_display = is_array($paid_settings['display'] ?? null) ? $paid_settings['display'] : [];
 		$paid_box_position = sanitize_key((string) ($paid_display['box_position'] ?? 'top'));
-		// Zibll positions: box_top | top | bottom | box_bottom (do not collapse).
+		// legacy positions: box_top | top | bottom | box_bottom (do not collapse).
 		if (!in_array($paid_box_position, ['box_top', 'top', 'bottom', 'box_bottom'], true)) {
 			$paid_box_position = 'top';
 		}
@@ -96,7 +96,7 @@ if (!function_exists('aksrt_single_build_context')) :
 			? aksrt_get_post_allow_view_data($post_id)
 			: ['allow' => true];
 		if (empty($allow_view['allow'])) {
-			// Zibll: pay box is skipped when allow_view denies.
+			// legacy: pay box is skipped when allow_view denies.
 			$show_pay_box = false;
 		}
 
@@ -182,7 +182,7 @@ endif;
 
 if (!function_exists('aksrt_single')) :
 	/**
-	 * Compose header + article + after-box (Zibll zib_single equivalent).
+	 * Compose header + article + after-box (legacy equivalent).
 	 *
 	 * @param array<string,mixed>|null $ctx Optional prebuilt context.
 	 */