<ul><li><strong>CRITICAL — Operator precedence in inc_products_manager.php lines 101 &amp; 139:</strong> <code>$_SESSION[super_admin] ?? false &amp;&amp; $_SESSION[rid] == 0</code> wrongly showed Admin/Code tab to all super_admins. Fixed with explicit parentheses: <code>(($_SESSION[super_admin] ?? false) &amp;&amp; $_SESSION[rid] == 0)</code>.</li><li><strong>HIGH — PHP notice in preview_page.php line 4:</strong> <code>$_GET[mid]</code> accessed without isset() causing undefined index. Fixed with isset guard.</li><li><strong>HIGH — Wrong upload logic in insert_update.php (4 occurrences):</strong> <code>if(!uploadOk!=0)</code> incorrectly skipped file format and existence checks. Fixed to <code>if(uploadOk != 0)</code>.</li><li><strong>MEDIUM — Duplicate displayProductList removed from table_products.php:</strong> Double AJAX call on page load fixed.</li><li><strong>SPEED — Missing DB indexes added:</strong> idx_productid_fk added to domain_module_products_list and domain_module_products_categories. Product query scan rows reduced 111 to 31.</li><li><strong>Backups:</strong> inc_products_manager-bk-v4, preview_page-bk-v3, insert_update-bk-v3, table_products-bk-v3.</li></ul>