Is your feature request related to a problem? Please describe.
Making a full backup, then deleting a file, making a partial backup and finally restoring the entire partial backup (using correct cli / manual steps) will also restore the "deleted" file.

Describe the solution you'd like
Track file deletions better to ensure that a partial that explicitly shouldn't have a file won't have it when restored.

Describe alternatives you've considered
N/A

Additional context
This will be done as part of the spi system, alongside a hopeful big change to improve #78 shenanigans.
The goal is to have a little filesystem watcher in the default differential / incremental backups that'll track all modification, creation and deletion of files, and ensure that is 100% mirrored. (relevant : https://discord.com/channels/1243006316599967846/1243033287363133470/1332686812799569992)

!target 4.0