Enhance API and routing for creator packs and samples

Commit notes

- Added a new API method to fetch creator details by slug, improving data retrieval for creator profiles. - Implemented a loader for creator packs, allowing for better integration with React Query. - Updated frontend routes to utilize the new creator pack loader, enhancing navigation and user experience. - Refactored sample data handling in the CreatorPackSamplePage for improved clarity and maintainability. - Introduced new types for better TypeScript support across the application.