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

src/js/main.ts

@@ -270,6 +270,7 @@ const init = async () => {
     'Flatten PDF': 'tools:flattenPdf',
     'Remove Metadata': 'tools:removeMetadata',
     'Change Permissions': 'tools:changePermissions',
+    'Email to PDF': 'tools:emailToPdf',
   };
 
   // Homepage-only tool grid rendering (not used on individual tool pages)