Calibre's Remove Book does something like this:
- creates a temporary folder in the library's parent folder e.g "D:\Calibre\Libraries\Books deleted e3hmxewg"
- copy's the selected library book folders into it
- does a permanent delete of the book folder(s) from from the library (and author folders if they're empty)
- does a soft delete of the temporary folder, which is a move to the Recycle Bin
The Recycle Bin Restore feature will recreate the temporary folder and its contents.
This has been discussed on numerous occasions, Kovid has stated his reasons why he does it this way, IIRC it relates to maintaining library integrity.
Maybe there should be a specific tool to Recover a book after a Recycle Bin Restore - i.e. basically Add from e.g. "D:\Calibre\Libraries\Books deleted e3hmxewg" and then delete that folder.
BR