(A) Interface with https://github.com/mv2devnul/taglib

(B) 2025-01-05 Study improvements of progress bar. E.g. the total expected size of the bar isn't indicated so we can't guess the completion percentage for the first copied track.

x (B) 2025-01-04 Add notion of "bonus" tracks, and allow to list them (so that one may list and delete them). Edit: since Discocl doesn't guess, this notion should be a tag and hence Discocl has nothing to do with it.

(B) Allow to compact filepaths. Either print filepaths relatively to the library (when paths are below the library) or squeeze directory components using only the first letter. During copy, one may display properly formatted tag values rather than filepaths.

Fix bug with library path with directories ending with a period, such as "U.K./...": FAT filesystems don't allow directories to end with a period  (except for "long directory names")

(C) Implement a library specification checker, including a "type checker" for hierarchy expressions

(C) Allow to move files rather than copy them. This would be necessary e.g. on almost full devices. We could add a protection that doesn't move files across filesystems.

Make the command status check whether each mentioned file still exist. Otherwise take appropriate action wrt to state when the file has disappeared (i.e. either remove the conflict or remove the import or transform a conflict into a correct import)

Stateful UI: add a command to reset all staged changes and conflicts

Stateful UI: save and load terminal-ui states to and from disk

Stateful UI: produce a command line interface that uses the stateful interaction
