Add sync-trigger for leaving the reader

[Lolle2000la]

Describe your suggested feature

When I binge something I might read many many chapters all at once. When I'm done I want to automatically have the progress synced to other devices to continue reading there. Currently, only a trigger for when I finish a chapter exists, which might mean many "useless" syncs and will still miss the page numbers.

Instead, a trigger for synchronization that goes off when I leave the reader would be very nice.

Other details

No response

Acknowledgements

• I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open or closed issue.
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• I have updated the app to version 1.11.0.
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