✨ Add printable materials feature for events

Introduce a new feature allowing users to download printable PDFs
with QR codes for events. Includes templates for table tents,
posters, flyers, and signs to enhance guest interaction.

🎨 Improve code formatting in tests

Refactor spacing in test assertions for better readability and consistency.

✅ Add tests for event zip generation and email

Implement tests for downloading event zips and sending email notifications.

⬆️ Upgrade rqrcode and rubyzip dependencies

Update rqrcode to version 3.1.1 and rubyzip to version 3.2.2 for
enhanced functionality and security improvements.