Flashcard Sorting Bug & Missing Page Link Option Post-Update

1. Flashcard Sorting Issue: When flashcards are created using the flashcard creation tool and sorted by 'page number', they revert to 'creation order' when re-accessed in the right sidebar. This impacts export order for Anki. Additionally, the 'manual order' drag-and-drop functionality is not working as expected.

2. Missing Manual Flashcard Linking: The option to manually create a flashcard and link it to a specific source page is no longer available after a recent update.