refactor(autoload): migrate theme classes to Composer PSR-4

Move 288 types from global AKSRT_* + inc/classes manual requires into
namespace AKSRT\{Domain} under src/AKSRT/, wire composer.json psr-4,
and slim bootstrap to helpers/modules/hooks only. Split multi-class
widget/gateway files, update admin contract audit paths, and document
the layout in ADR/README.

tag.php

@@ -15,8 +15,8 @@ if (!$term instanceof WP_Term) {
 	return;
 }
 
-$archive_settings = class_exists('AKSRT_Term_Meta')
-	? AKSRT_Term_Meta::resolve_archive_settings($term)
+$archive_settings = class_exists('\AKSRT\Core\TermMeta')
+	? \AKSRT\Core\TermMeta::resolve_archive_settings($term)
 	: [
 		'layout_mode'  => 'card',
 		'header_style' => 'simple',
@@ -35,8 +35,8 @@ $description = !empty($archive_settings['show_desc']) ? wp_kses_post((string) $a
 $header_style = (string) $archive_settings['header_style'];
 $layout_mode = (string) $archive_settings['layout_mode'];
 $card_style = (string) ($archive_settings['card_style'] ?? 'standard');
-$filter_settings = class_exists('AKSRT_Settings')
-	? AKSRT_Settings::get_post_filter_settings()
+$filter_settings = class_exists('\AKSRT\Settings\Settings')
+	? \AKSRT\Settings\Settings::get_post_filter_settings()
 	: ['enabled' => false, 'sort' => false, 'ajax_enabled' => false];
 if (!empty($filter_settings['enabled']) && !in_array('tag', $filter_settings['custom_filter_show'] ?? ['cat', 'tag'], true)) {
 	$filter_settings['enabled'] = false;