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/WidgetForumHotTopics.php

@@ -7,9 +7,12 @@
 
 namespace AKSRT\Widgets;
 
+use AKSRT\Widgets\Traits\CommonWidgetFields;
+
 defined('ABSPATH') || exit;
 
 class WidgetForumHotTopics extends \WP_Widget {
+	use CommonWidgetFields;
 
 	public function __construct() {
 		parent::__construct(
@@ -179,9 +182,9 @@ class WidgetForumHotTopics extends \WP_Widget {
 		echo $args['before_widget']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
 		echo $args['before_title'] . esc_html($title) . $args['after_title']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
 		$rest = rest_url('aksrt/v1/widgets/forum-topics');
-		$in_affix = !empty($instance['in_affix']);
-		$wrap = 'ajaxpager' . ($in_affix ? ' is-affix' : '');
-		echo '<div class="' . esc_attr($wrap) . '" data-aksrt-ajaxpager data-aksrt-ajax-url="' . esc_url($rest) . '"' . ($in_affix ? ' data-affix="true"' : '') . '>';
+		$affix = function_exists('aksrt_widget_affix_attrs') ? aksrt_widget_affix_attrs($instance) : ['class' => '', 'attr' => ''];
+		$wrap = 'ajaxpager' . $affix['class'];
+		echo '<div class="' . esc_attr($wrap) . '" data-aksrt-ajaxpager data-aksrt-ajax-url="' . esc_url($rest) . '"' . $affix['attr'] . '>';
 		echo $payload['html']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
 		echo $payload['paginate_html']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
 		echo '<div class="post_ajax_loader" data-aksrt-ajax-loader data-aksrt-ajax-loader-hide hidden></div>';
@@ -245,9 +248,7 @@ class WidgetForumHotTopics extends \WP_Widget {
 				</select>
 			</label>
 		</p>
-		<p>
-			<label><input type="checkbox" name="<?php echo esc_attr($this->get_field_name('in_affix')); ?>" value="1" <?php checked(!empty($instance['in_affix'])); ?>> <?php esc_html_e('侧栏随动', 'aksrt'); ?></label>
-		</p>
+		<?php $this->render_common_form_section($instance); ?>
 		<?php
 	}
 
@@ -260,7 +261,7 @@ class WidgetForumHotTopics extends \WP_Widget {
 		if (!in_array($style, ['mini', 'rank'], true)) {
 			$style = 'mini';
 		}
-		return [
+		return $this->update_common_fields($new_instance, $old_instance, [
 			'title'    => sanitize_text_field($new_instance['title'] ?? ''),
 			'count'    => max(1, min(20, (int) ($new_instance['count'] ?? 5))),
 			'period'   => in_array($new_instance['period'] ?? '', ['all', 'week', 'month'], true) ? $new_instance['period'] : 'week',
@@ -268,6 +269,6 @@ class WidgetForumHotTopics extends \WP_Widget {
 			'style'    => $style,
 			'plate'    => max(0, (int) ($new_instance['plate'] ?? 0)),
 			'paginate' => in_array(sanitize_key((string) ($new_instance['paginate'] ?? 'ajax')), ['none', 'ajax', 'number'], true) ? sanitize_key((string) ($new_instance['paginate'] ?? 'ajax')) : 'ajax',
-		];
+		]);
 	}
 }