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/forum/class-aksrt-forum.php

@@ -94,7 +94,10 @@ class AKSRT_Forum {
 
     private function draft_service(): AKSRT_Forum_Draft_Service {
         if (!$this->draft_svc) {
-            require_once __DIR__ . '/forum/class-aksrt-forum-draft-service.php';
+            // Draft service is loaded by bootstrap before this class.
+            if (!class_exists('AKSRT_Forum_Draft_Service', false)) {
+                require_once __DIR__ . '/class-aksrt-forum-draft-service.php';
+            }
             $this->draft_svc = new AKSRT_Forum_Draft_Service($this);
         }
         return $this->draft_svc;