Refactored MainActivity and its Compose UI components to use a single
onAction: (MainAction) -> Unit callback. This significantly simplifies
component signatures and centralizes interaction logic.
- Updated MainContract.kt to include all UI-triggered actions.
- Modified MainScreen and sub-components (TopBar, BottomBar, Drawer, etc.)
to use the unified onAction dispatcher.
- Implemented a centralized action handler in MainActivity to dispatch
between ViewModel and Activity-specific tasks.
- Removed redundant ImportConfigViaSub action.
- Moved QR code generation state into MainUiState for MVI consistency.
This change reduces parameter drilling and improves maintainability of
the main interface.