Configuration override for operations that currently only affect files inside the library directory

I have duplicate_action: ask so i type 'r' to remove the old ones on import. I just noticed that the filesystem is not affected, so 2 copies of the albums now exist - only the database is affected on pressing 'r'. The only way I can fix this is to 'beet mv' the entire library to a temporary location, remove the files from the original location, then 'beet mv' everything back.

Start by tracing how duplicate_action: ask handles the 'r' response during import and where the beets import command limits filesystem changes to the library directory. Done means a configuration override can control these filesystem operations consistently with the existing database update, including files outside the library.

Written by the indexing model from the issue text.