feat: strip YAML frontmatter from toMarkdown output

Author: yanglbme

src/index.ts

@@ -184,6 +184,9 @@ export default {
 
       let markdown = result.data ?? '';
 
+      // Strip YAML frontmatter if present (generated by Workers AI toMarkdown)
+      markdown = markdown.replace(/^---\n[\s\S]*?\n---\n*/, '');
+
       // Proxy WeChat images through R2 (if configured)
       const rawHtmlForImages = isHtmlContent(contentType) ? new TextDecoder().decode(body) : '';