fix(workspace): group text and code blocks cleanly under headings on paste

frontend/src/lib/markdown.tsx

@@ -8,7 +8,7 @@ import React from 'react';
  * - `code`
  * - [label](url)
  */
-export function renderInlineMarkdown(text: string): React.ReactNode[] {
+function renderInlineTokens(text: string): React.ReactNode[] {
   if (!text) return [];
 
   const regex = /(`[^`]+`|\*\*[^*]+\*\*|__[^_]+__|~~[^~]+~~|\*[^*]+\*|_[^_]+_|\[([^\]]+)\]\(([^)]+)\))/g;
@@ -83,6 +83,55 @@ export function renderInlineMarkdown(text: string): React.ReactNode[] {
   return elements;
 }
 
+/**
+ * Parses inline markdown and fenced code blocks:
+ * - ```lang\ncode\n```
+ * - **bold** or __bold__
+ * - *italic* or _italic_
+ * - ~~strikethrough~~
+ * - `code`
+ * - [label](url)
+ */
+export function renderInlineMarkdown(text: string): React.ReactNode[] {
+  if (!text) return [];
+
+  if (text.includes('```')) {
+    const codeBlockRegex = /(```[a-zA-Z0-9_-]*\r?\n[\s\S]*?```|```[\s\S]*?```)/g;
+    const parts = text.split(codeBlockRegex);
+    const nodes: React.ReactNode[] = [];
+
+    parts.forEach((part, partIdx) => {
+      if (part.startsWith('```') && part.endsWith('```')) {
+        const lines = part.split(/\r?\n/);
+        const firstLine = lines[0].slice(3).trim();
+        const codeLines = lines.slice(1, lines.length - 1);
+        const code = codeLines.join('\n');
+        nodes.push(
+          <div
+            key={`fenced-${partIdx}`}
+            className="p-2.5 my-2 rounded bg-code text-accent font-mono text-xs overflow-x-auto border border-border/60 select-text"
+          >
+            {firstLine && (
+              <div className="text-[10px] text-faint uppercase font-sans pb-1 select-none">
+                {firstLine}
+              </div>
+            )}
+            <pre className="whitespace-pre overflow-x-auto font-mono text-status-ok leading-relaxed">
+              <code>{code}</code>
+            </pre>
+          </div>
+        );
+      } else if (part) {
+        nodes.push(...renderInlineTokens(part));
+      }
+    });
+
+    return nodes;
+  }
+
+  return renderInlineTokens(text);
+}
+
 export function MarkdownViewer({ content, className = '' }: { content: string; className?: string }) {
   if (!content) return null;