Add markdown rendering utility for bold, italic, and inline code

src/markdown.ts

@@ -0,0 +1,21 @@
+export function renderMarkdown(text: string): string {
+  // Extract code spans first so their contents aren't processed as bold/italic
+  const codeSpans: string[] = []
+  let result = text.replace(/`([^`]+)`/g, (_, code) => {
+    codeSpans.push(code)
+    return `\x00CODE${codeSpans.length - 1}\x00`
+  })
+
+  // Bold: **text**
+  result = result.replace(/\*\*(.+?)\*\*/g, "\x1b[1m$1\x1b[22m")
+
+  // Italic: *text*
+  result = result.replace(/\*(.+?)\*/g, "\x1b[3m$1\x1b[23m")
+
+  // Restore code spans as light blue
+  result = result.replace(/\x00CODE(\d+)\x00/g, (_, i) => {
+    return `\x1b[94m${codeSpans[parseInt(i)]}\x1b[39m`
+  })
+
+  return result
+}