Switched to Slugs for Demo Apps

• Updated demo apps to use slugs instead of IDs in routes and database queries.

• Enables better support for programmatic SEO, allowing cleaner and more descriptive URLs for user-generated content.

• Simplifies navigation and improves readability for both users and search engines.
  
  

This change significantly enhances the SEO potential of demo apps and prepares them for scalable content generation.