fix: replace JS lookbehind regex (Safari compat) in markdown renderer

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-server/src/routes/web.rs

@@ -893,8 +893,8 @@ function renderMd(text) {
   s = s.replace(/`([^`]+)`/g, '<code>$1</code>');
   // Bold: **...**
   s = s.replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>');
-  // Italic: *...*
-  s = s.replace(/(?<!\*)\*(?!\*)(.+?)(?<!\*)\*(?!\*)/g, '<em>$1</em>');
+  // Italic: *...* (single asterisk, not double)
+  s = s.replace(/([^*]|^)\*([^*]+?)\*([^*]|$)/g, '$1<em>$2</em>$3');
   // Headers: ### ... (at line start)
   s = s.replace(/^### (.+)$/gm, '<h3>$1</h3>');
   s = s.replace(/^## (.+)$/gm, '<h2>$1</h2>');