Fixed all PHP 8.1+ errors across 7 accordion files in Web Pages settings panel. (1) htmlspecialchars() null warnings — added ?? empty-string fallback in content.php (5 calls), details.php (2 calls), banner.php (3 calls), menu_embed_url.php (4 calls). (2) Undefined array key warnings — added ?? fallback for $siteConfigMenuResult and $moduleInfoResult fields in content.php, display.php, banner.php. (3) Undefined $_SESSION keys — added ?? fallback for super_admin, usersecuritylevel, YPTemplateID, YPSiteLinkID, LIVE_SITE_NAME. (4) Replaced extract() calls in content.php with explicit variable assignments. (5) Fixed let→var for 17 global-scope declarations across menu_card.php, banner.php, menu_embed_url.php, security.php to prevent SyntaxError on re-injection via jQuery .html(). Tested all menu types (Webpage/Module/Link) — zero errors across 8 different menu items.