feat(email-to-pdf): add inline images, clickable links, and embedded attachments

- Add CID inline image support via base64 data URI replacement
- Implement clickable link extraction from HTML anchors using regex
- Embed email attachments into PDF using pymupdf embfile_add
- Reduce font sizes for more compact PDF output (18px subject, 12px body)
- Format date with timezone (UTC+HH:MM) while preserving original time
- Clean email address formatting (Name (email) instead of <brackets>)
- Add UI options: page size selector, CC/BCC toggle, attachments toggle

public/sitemap.xml

@@ -281,6 +281,12 @@
     <changefreq>monthly</changefreq>
     <priority>0.5</priority>
   </url>
+  <url>
+    <loc>https://www.bentopdf.com/email-to-pdf</loc>
+    <lastmod>2026-01-08</lastmod>
+    <changefreq>monthly</changefreq>
+    <priority>0.7</priority>
+  </url>
   <url>
     <loc>https://www.bentopdf.com/xps-to-pdf</loc>
     <lastmod>2024-12-28</lastmod>