SSH Proxy 0.3.0

feat: ✨ Add widget, backup, and key storage improvements

BREAKING CHANGE: ⚠️ This update introduces a new, more secure method for storing SSH key passwords using the Android Keystore system. As part of this migration, old, less secure key files will be removed. Please ensure you have a backup of your private keys before updating if you wish to preserve them outside of the app's new encrypted storage.

This commit introduces several new features and improvements:

- 🚀 **Home Screen Widget:** A new widget for the home screen allows for quick connection and disconnection to the VPN. It displays the current connection status with a colored circle.

- 💾 **Backup & Restore:** Users can now export and import their servers and keys. This makes it easy to transfer settings between devices.

- 🔐 **Enhanced Key Storage:** SSH key passwords are now stored more securely using the Android Keystore system. This improves the overall security of the application.

- 🧪 **New Connection Test UI:** The connection testing feature has been refactored into a BottomSheet component, providing a better user experience.

- 🐛 **Bug Fixes & Stability:** This release also includes various bug fixes and improvements to connection stability and error handling.