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/classes/settings/class-aksrt-settings-theme-search.php

@@ -483,7 +483,7 @@ class AKSRT_Settings_Theme_Search {
         $s = AKSRT_Settings::get_all();
 
         $position = sanitize_key((string) ($s['sidebar_position'] ?? 'right'));
-        $width    = max(200, min(400, (int) ($s['sidebar_width'] ?? 300)));
+        $width    = max(200, min(400, (int) ($s['sidebar_width'] ?? 311)));
 
         return [
             'enabled'  => !isset($s['sidebar_enabled']) || !empty($s['sidebar_enabled']),