Enhanced SenderPdfImageEditor with page navigation features:
- Added methods to navigate to first, previous, next, last, or specific pages.
- Introduced `_currentPage` to track and validate the current page.
- Implemented `OnParametersSet` to initialize/clamp `_currentPage`.
- Integrated JavaScript interop for scrolling and visible page detection.
Updated SenderPdfImageEditorToolbar:
- Added navigation buttons with enable/disable states.
- Replaced static page display with input and dropdown for page selection.
- Added event callbacks for navigation actions.
Styled new toolbar elements in `envelope-viewer.css` and added:
- Input field and dropdown for page selection.
- Adjusted layout and appearance of navigation controls.
Extended `envelope-editor.js` with:
- `scrollToPdfPage` for smooth scrolling to a specific page.
- `getVisiblePdfPageNumber` to detect the most visible page.
TekH
8386b85592