refactor(classes): organize inc/classes into domain folders

Move ~94 root class shells and root *-traits into domain directories
(core, auth, user, credits, content, payment/gateways, forum, shop,
sms, ai, messages, extensions, widgets, settings, admin). Update
bootstrap require paths, co-locate traits with owners, fix forum/user
relative requires, drop duplicate shop controller requires, and wire
home-modules load. Path-only; class names and init order unchanged.

inc/classes/core/class-aksrt-db-migrator.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * AKSRT DB Migrator
+ *
+ * Maintains runtime tables (credits / download tokens / shop / forum support, etc.).
+ * Schema only via dbDelta — no option/data migration, no legacy option dual-write.
+ *
+ * Trigger:
+ *   1. after_switch_theme
+ *   2. admin_init when aksrt_db_schema_version !== SCHEMA_VERSION
+ *
+ * @package AKSRT
+ */
+
+defined('ABSPATH') || exit;
+
+class AKSRT_DB_Migrator {
+    use AKSRT_DB_Migrator_Part_2;
+    use AKSRT_DB_Migrator_Part_3;
+
+    /** Current schema version; changing it re-runs dbDelta. */
+    const SCHEMA_VERSION = '1.15.0';
+
+    const OPT_KEY = 'aksrt_db_schema_version';
+
+    /**
+     * Historical flag still readable by older code paths.
+     * Plate CPT is now native when registered; prefer post_type_exists().
+     */
+    const OPT_PLATE_CPT_MIGRATED = 'aksrt_plate_cpt_migrated';
+
+    /**
+     * Register hooks.
+     */
+    public static function init(): void {
+        add_action('after_switch_theme', [self::class, 'maybe_migrate']);
+        add_action('admin_init', [self::class, 'maybe_migrate']);
+    }
+
+    /**
+     * Run table schema upgrade when version mismatches.
+     */
+    public static function maybe_migrate(): void {
+        $current = get_option(self::OPT_KEY, '');
+        if ($current === self::SCHEMA_VERSION) {
+            return;
+        }
+
+        self::run();
+        update_option(self::OPT_KEY, self::SCHEMA_VERSION);
+    }
+}