Optimize the sway-by-example front-end page according to the requirements:

1. Optimize the homepage display format
2. Add wallet connect and disconnect buttons, with support for viewing the currently connected wallet
3. Add a return to homepage button
4. Optimize the style of the language switch button
5. Support switching to the previous/next case

How to contribute: use Github PR Workflow

Github link:
https://github.com/fuelchina/sway-by-example