Add image rendering to markdown parser

Support ![alt](url) syntax in comments/descriptions. Images are only
rendered for http/https URLs. Style via .md-image (max-width, border,
block display) consistent with existing .lt-markdown img rule.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/js/markdown.js

@@ -41,6 +41,14 @@ function parseMarkdown(markdown) {
     html = html.replace(/\*(.+?)\*/g, '<em>$1</em>');
     html = html.replace(/_(.+?)_/g, '<em>$1</em>');
 
+    // Images ![alt](url) - must come before link handler
+    html = html.replace(/!\[([^\]]*)\]\(([^)]+)\)/g, function(match, alt, url) {
+        if (/^https?:/i.test(url)) {
+            return '<img src="' + url + '" alt="' + alt + '" class="md-image" loading="lazy">';
+        }
+        return match;
+    });
+
     // Links [text](url) - only allow safe protocols
     html = html.replace(/\[([^\]]+)\]\(([^)]+)\)/g, function(match, text, url) {
         // Only allow http, https, mailto protocols