feat(phase2): shared common-form layer + CommonWidgetFields trait for all widgets

- Extract Zibll CSF_Widget::params() common-field parity into
  inc/modules/widget-common.php (required by widgets-register.php to keep
  both files <1000 lines): subtitle, title_style(simple/big), title_highlight
  +color, title_link x3, title_link_style colors, sidebar_affix, show_type
  (all/only_pc/only_sm), show_id_type(show/hide), show_ids, animation_in,
  animation_repeat, layout_pin_pc/m, layout_bg(white/dark). Adds
  normalize_link/normalize_bg helpers, affix_attrs, common_wrapper_attr,
  render_title, animation_class. Back-compat normalizes legacy tokens
  (in_affix->sidebar_affix, pc/only_pc, include/exclude->show/hide).
- Add src/AKSRT/Widgets/Traits/CommonWidgetFields.php trait
  (render_common_form_section + update_common_fields).
- Wire all 57 widgets to use the trait; migrate the 16 hand-rolled in_affix
  implementations to shared sidebar_affix (fixes 6 latent bugs where
  in_affix was never persisted). SearchWidget intentionally skips the shared
  form section (its business show_type collides) but adopts the affix helper.
- widget_display_callback parity verified via tmp assertion script.

Refs .specs/plans/zibll-widgets-1to1.md Phase 2 (US1/US5)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AKSRT/Widgets/SearchWidget.php

@@ -7,9 +7,12 @@
 
 namespace AKSRT\Widgets;
 
+use AKSRT\Widgets\Traits\CommonWidgetFields;
+
 defined('ABSPATH') || exit;
 
 class SearchWidget extends \WP_Widget {
+	use CommonWidgetFields;
 
 	public function __construct() {
 		parent::__construct('aksrt_search', esc_html__('AKSRT 搜索', 'aksrt'), [
@@ -32,10 +35,20 @@ class SearchWidget extends \WP_Widget {
 		$show_kw      = !empty($instance['show_keywords']);
 		$show_history = !empty($instance['show_history']);
 		$show_types   = !empty($instance['show_type']) || !isset($instance['show_type']);
+		// NOTE: SearchWidget owns a business `show_type` checkbox (search-type
+		// toggle) that shares the key name with the common `show_type` (device
+		// visibility). To avoid an admin-form collision, this widget does NOT
+		// render the shared common-form section (render_common_form_section is
+		// intentionally not called). The shared affix helper is still wired in
+		// widget() via aksrt_widget_affix_attrs(), and update_common_fields()
+		// persists common keys — but note the shared show_type cannot be set
+		// here, so display_callback treats it as 'all' (always visible).
 		$show_cat     = !empty($instance['show_input_cat']);
 		$kw_title     = sanitize_text_field((string) ($instance['keywords_title'] ?? __('热门搜索', 'aksrt')));
 		$more_but     = sanitize_text_field((string) ($instance['more_but'] ?? ''));
 		$more_url     = esc_url_raw(trim((string) ($instance['more_but_url'] ?? '')));
+		// Affix helper (shared layer sidebar_affix).
+		$affix        = function_exists('aksrt_widget_affix_attrs') ? aksrt_widget_affix_attrs($instance) : ['class' => '', 'attr' => ''];
 
 		$state = function_exists('aksrt_get_search_form_state')
 			? aksrt_get_search_form_state()
@@ -109,7 +122,7 @@ class SearchWidget extends \WP_Widget {
 
 		$uid = 'aksrt-sw-' . esc_attr($this->id);
 		?>
-		<div class="widget-search-box aksrt-search-widget search-input<?php echo !empty($instance['in_affix']) ? ' is-affix' : ''; ?>" id="<?php echo $uid; ?>"<?php echo !empty($instance['in_affix']) ? ' data-affix="true"' : ''; ?>>
+		<div class="widget-search-box aksrt-search-widget search-input<?php echo $affix['class']; ?>" id="<?php echo $uid; ?>"<?php echo $affix['attr']; ?>>
 			<form
 				role="search"
 				method="get"
@@ -239,8 +252,7 @@ class SearchWidget extends \WP_Widget {
 			<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('show_type')); ?>" value="1" <?php checked(!empty($instance['show_type']) || !isset($instance['show_type'])); ?>> <?php esc_html_e('显示类型切换（≥2 种时）', 'aksrt'); ?></label><br>
 			<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('show_input_cat')); ?>" value="1" <?php checked(!empty($instance['show_input_cat'])); ?>> <?php esc_html_e('显示分类筛选', 'aksrt'); ?></label><br>
 			<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('show_keywords')); ?>" value="1" <?php checked(!empty($instance['show_keywords'])); ?>> <?php esc_html_e('显示热门关键词', 'aksrt'); ?></label><br>
-			<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('show_history')); ?>" value="1" <?php checked(!empty($instance['show_history'])); ?>> <?php esc_html_e('显示搜索历史', 'aksrt'); ?></label><br>
-				<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('in_affix')); ?>" value="1" <?php checked(!empty($instance['in_affix'])); ?>> <?php esc_html_e('侧栏随动', 'aksrt'); ?></label>
+			<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('show_history')); ?>" value="1" <?php checked(!empty($instance['show_history'])); ?>> <?php esc_html_e('显示搜索历史', 'aksrt'); ?></label>
 		</p>
 		<p>
 			<label><?php esc_html_e('默认类型', 'aksrt'); ?>
@@ -281,11 +293,18 @@ class SearchWidget extends \WP_Widget {
 				<input class="widefat" type="text" name="<?php echo esc_attr($this->get_field_name('more_but_url')); ?>" value="<?php echo esc_attr((string) ($instance['more_but_url'] ?? '')); ?>">
 			</label>
 		</p>
+		<?php // Common-form section intentionally skipped: SearchWidget owns a
+		      // business `show_type` checkbox (search-type toggle) that collides
+		      // with the shared common `show_type` (device visibility). The
+		      // shared affix/display/animation/layout fields are therefore not
+		      // rendered here; update_common_fields() below still persists any
+		      // common keys submitted through other surfaces, and the affix
+		      // helper is wired in widget() via aksrt_widget_affix_attrs(). ?>
 		<?php
 	}
 
 	public function update($new_instance, $old_instance): array {
-		return [
+		return $this->update_common_fields($new_instance, $old_instance, [
 			'title'           => sanitize_text_field((string) ($new_instance['title'] ?? '')),
 			'placeholder'     => sanitize_text_field((string) ($new_instance['placeholder'] ?? '')),
 			'show_keywords'   => !empty($new_instance['show_keywords']) ? 1 : 0,
@@ -299,7 +318,6 @@ class SearchWidget extends \WP_Widget {
 			'keywords'        => sanitize_textarea_field((string) ($new_instance['keywords'] ?? '')),
 			'more_but'        => sanitize_text_field((string) ($new_instance['more_but'] ?? '')),
 			'more_but_url'    => esc_url_raw(trim((string) ($new_instance['more_but_url'] ?? ''))),
-			'in_affix'        => !empty($new_instance['in_affix']) ? 1 : 0,
-		];
+		]);
 	}
 }