feat: Add loading animation while fetching course data

[Varundeep111]

Added a loading animation to improve user experience while course data is being fetched from the backend. Previously, users would see an empty state message while data was loading, which could be confusing. Now, a spinner animation clearly indicates that data is being loaded.

• Added loading state management in CourseSummaryController
• Implemented SpinKitPulse loading animation from flutter_spinkit package
• Added proper error handling with user feedback
• Updated UI to show loading state before showing empty state or course data

Dependencies Added

• flutter_spinkit: ^5.2.0

Notes for Reviewers

• Loading animation color matches the app's accent color (0xFF4CAF50)
• The loading state is managed through GetX observables
• Error handling includes user-friendly snackbar messages

[angrezichatterbox]

Thanks for the PR @98021Varundeep Will get to review it soon :)

[angrezichatterbox]

Fantastic job on the PR, @98021Varundeep! The loading animation is excellent—it really enhances the user experience. If you’re up for it, could you also take a look at the remaining issues? Your insights would be incredibly valuable, and any suggestions you have to improve the app would be much appreciated!

[Varundeep111]

Thank you so much! 🙌 I’m really glad you liked the loading animation—it’s rewarding to see it making a positive impact on the user experience. I’d be happy to dive into the remaining issues and share my thoughts. I’ll review them and see if there are opportunities for improvements or optimizations. Appreciate the feedback and trust—let’s keep enhancing the app! 🚀