- Introduced UserMessage widget for displaying user input with a styled prompt.
- Updated onboarding steps to include UI backend selection (Rich CLI or Textual TUI).
- Modified EvoScientistConfig to store selected UI backend.
- Enhanced configuration handling to support UI backend environment variable.
- Updated README with new UI backend options and commands.
- Added tests for new UI backend functionality and UserMessage widget.
- Removed obsolete test files and ensured existing tests are updated accordingly.