phsl / new-api

✨feat(ui): Add loading states to all authentication buttons

Add loading indicators to improve user experience during authentication processes:
- Implement loading states for all login and registration buttons
- Add try/catch/finally structure to properly handle async operations
- Create wrapper functions for OAuth redirect operations
- Set loading state for verification code submission
- Update modal confirmation buttons with loading state
- Add proper error handling with user feedback
- Split generic loading state into specific state variables

This change enhances user experience by providing clear visual feedback
during authentication actions.