Refactor MainPage.xaml layout and improve control bindings

- Commented out the outer `ScrollViewer` wrapping the entire content.
- Moved `ContentArea` `Grid` directly within the `Page`.
- Added `ScrollViewer` elements within each `PivotItem` for better scrolling.
- Updated `ProgressRingUserControl` and `OperationResultDialog` for proper loading and display.
- Bound `ActionQuestionUserControl` width and height to `ContentArea` and added action/visibility bindings.
- Ensured proper loading and visibility of `LogBookUserControl`.
- Moved and updated `InAppNotification` for file save success messages.
- Improved overall structure and layout of `MainPage.xaml`.