fix(widgets): restore single-card reference UI for search and quote widgets

The 搜索框 and 一言 sidebar widgets fell into the generic renderer branch, so
they rendered a .jio-panel card wrapping a second bespoke card
(.jio-widget-search / .jio-widget-quote). In-article 一言 also used
divergent modifier classes and an extra hover rule.

- search: render through the shared jio_get_search_box() (legacy keyword,
  history and category pickers) inside one reference card, mirroring the
  reference widget's markup and title default 「搜索」
- quote: render the reference .yiyan-box card itself as the click root; the
  shell now emits only the reference widget-container/title wrapper
- article 一言: adopt the reference class lists for header, footer and the
  standalone after-article box; drop the invented yiyan--* modifiers and
  the duplicate hover/opacity rules
- client: fill .cn/.en in the reference order (first line .cn, second .en)
  and drop the stale window.JioYiyan bridge plus the dead qv-yiyan.php AJAX
  path in runtime main.js
- schema: replace the ad-hoc search_style radio with the reference switches
  (keywords, history, input category, more_cats) and default title
- assets: enqueue assets/js/yiyan.js through the quote widget's asset list

Tests: widget-system suite 820/821 (the one failure is the pre-existing
frontend-lifecycle theme-init stub); new search/quote card contracts pass.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

inc/helpers/jio-yiyan.php

@@ -60,6 +60,7 @@ if (!function_exists('jio_render_yiyan_block')) :
 		if (strpos($class, 'jio-yiyan') === false) {
 			$class = trim($class . ' jio-yiyan');
 		}
+		// 与参考结构一致：.yiyan 初始为空，由脚本写入 .cn（首行）与 .en（次行）。
 		$html = '<div class="' . esc_attr($class) . '"'
 			. ' data-jio-yiyan'
 			. ' data-endpoint="' . esc_url(admin_url('admin-ajax.php')) . '"'
@@ -68,7 +69,7 @@ if (!function_exists('jio_render_yiyan_block')) :
 			. ' role="button" tabindex="0"'
 			. ' aria-label="' . esc_attr__('点击切换一言', 'jio') . '"'
 			. ' aria-live="polite">'
-			. '<div class="yiyan"><div class="en"></div><div class="cn">' . esc_html__('加载中…', 'jio') . '</div></div>'
+			. '<div class="yiyan"></div>'
 			. '</div>';
 		return $html;
 	}