Code Refactoring and Enhancement for Example App Compliance with Dart Conventions

[AndrewDongminYoo]

This pull request includes several key changes aimed at improving the code quality and maintainability of the Flutter Carousel Slider project. The updates include:

1. Code Refactoring for Dart Conventions:

   • Refactored the code across multiple files to better adhere to Dart's best practices and coding conventions. This includes improved naming conventions, better structuring of code, and overall cleanup.

2. Enhancement in Example App:

   • Added widget keys where necessary to ensure better performance and state management.
   • Introduced the const keyword across various widgets in the example app to optimize build times and memory usage.
   • Updated UI elements and widget structures to enhance readability and efficiency.

Changes Made:

• Significant changes in example/lib/main.dart to integrate const constructors and improve overall code readability.
• Minor but crucial updates in lib/carousel_controller.dart to ensure better adherence to Dart conventions.
• Refined the code in lib/carousel_slider.dart, including replacing Container with SizedBox where applicable, and adjusting the usage of Transform.scale for better layout handling.

Impact:
These changes improve the consistency and maintainability of the codebase, reduce potential bugs related to widget rebuilds, and make the example app more efficient.

Please review the changes and provide feedback or approval for merging into the main branch.

Commit Details:

• Refactoring for better Dart convention compliance.
• Addition of widget keys and const keyword for performance optimization.
• 129 additions and 89 deletions across three files.