refactor: create Admin Manager class and move menu registration

admin/includes/class-admin-manager.php

@@ -0,0 +1,35 @@
+<?php
+/**
+ * WP ALLSTARS Admin Manager
+ * 
+ * Handles admin-related functionality including menu registration, 
+ * script enqueueing, and admin page rendering.
+ */
+
+if (!defined('ABSPATH')) {
+    exit; // Exit if accessed directly
+}
+
+class WP_Allstars_Admin_Manager {
+    
+    /**
+     * Initialize the class
+     */
+    public static function init() {
+        // Register hooks - we'll add more as we refactor each function
+        add_action('admin_menu', array(__CLASS__, 'register_admin_menu'));
+    }
+    
+    /**
+     * Register the admin menu item
+     */
+    public static function register_admin_menu() {
+        add_options_page(
+            'WP ALLSTARS Settings',
+            'WP ALLSTARS',
+            'manage_options',
+            'wp-allstars',
+            'wp_allstars_settings_page'
+        );
+    }
+}