feat(frontend): adopt zibll site-layout-1/2/3 float dual-column system

Wire settings-driven sidebar visibility and body site-layout classes,
replace content-layout CSS grid with Zibll float geometry, move sidebar
DOM to content-wrap sibling across single/archive/page/home, and add
post meta show_layout overrides.

inc/helpers/aksrt-single.php

@@ -99,9 +99,9 @@ if (!function_exists('aksrt_single_build_context')) :
 			$show_pay_box = false;
 		}
 
-		$aside_widgets = is_active_sidebar('sidebar-article')
-			|| is_active_sidebar('all_sidebar_top')
-			|| is_active_sidebar('all_sidebar_bottom');
+		$show_aside = function_exists('aksrt_is_show_sidebar')
+				? aksrt_is_show_sidebar()
+				: false;
 
 		return [
 			'post_id'           => $post_id,
@@ -138,7 +138,7 @@ if (!function_exists('aksrt_single_build_context')) :
 			'paid_box_position' => $paid_box_position,
 			'breadcrumbs_html'  => $breadcrumbs_html,
 			'status_badge'      => $status_badge,
-			'show_aside'        => $aside_widgets || $show_toc || $has_download || $show_pay_box,
+			'show_aside'        => $show_aside,
 			'toc_title'         => __('文章目录', 'aksrt'),
 		];
 	}
@@ -948,7 +948,7 @@ if (!function_exists('aksrt_single_render_aside')) :
 			return;
 		}
 		?>
-		<aside class="sidebar content-layout__aside" role="complementary" aria-label="<?php esc_attr_e('侧栏', 'aksrt'); ?>">
+		<div class="sidebar" role="complementary" aria-label="<?php esc_attr_e('侧栏', 'aksrt'); ?>">
 			<?php if (!empty($ctx['has_download'])) : ?>
 				<?php get_template_part('templates/parts/resource-meta-box'); ?>
 			<?php endif; ?>
@@ -971,7 +971,7 @@ if (!function_exists('aksrt_single_render_aside')) :
 			<?php if (is_active_sidebar('all_sidebar_bottom')) : ?>
 				<?php dynamic_sidebar('all_sidebar_bottom'); ?>
 			<?php endif; ?>
-		</aside>
+		</div>
 		<?php
 	}
 endif;