feat: add email sharing functionality, canonical URLs, and enhance metadata for SEO

php/icons.php

@@ -20,6 +20,8 @@ if (!function_exists('blowdit_icon')) {
 			'chevron-left'  => '<path d="M15 18l-6-6 6-6"/>',
 			'chevron-right' => '<path d="M9 18l6-6-6-6"/>',
 			'house'         => '<path d="M3 10.5 12 3l9 7.5"/><path d="M5 9.5V21h14V9.5"/>',
+			'link'          => '<path d="M9 17H7A5 5 0 0 1 7 7h2"/><path d="M15 7h2a5 5 0 0 1 0 10h-2"/><path d="M8 12h8"/>',
+			'share'         => '<circle cx="18" cy="5" r="3"/><circle cx="6" cy="12" r="3"/><circle cx="18" cy="19" r="3"/><path d="M8.6 13.5l6.8 4M15.4 6.5l-6.8 4"/>',
 			// --- Theme picker (mirror in blowdit.js) ---
 			'sun'           => '<circle cx="12" cy="12" r="4"/><path d="M12 2v2M12 20v2M4.9 4.9l1.4 1.4M17.7 17.7l1.4 1.4M2 12h2M20 12h2M4.9 19.1l1.4-1.4M17.7 6.3l1.4-1.4"/>',
 			'moon'          => '<path d="M21 12.8A9 9 0 1 1 11.2 3 7 7 0 0 0 21 12.8z"/>',