Nothing is logged.

Report what the service does that no `FantomasResponse` can carry: which Fantomas a folder resolved to and where it was found, when none could be found at all, and when a daemon is started or fails to start. Resolving to a tool on the PATH is the one a user most needs to see, since it formats exactly as successfully as the version their repository pins. Called on whichever thread the work happened on, which for tool resolution is the service's own mailbox rather than the caller's, and never more than once per folder for a resolution: a folder already mapped to a version does not resolve again. A delegate that throws is swallowed, because these are called from inside that mailbox and an exception out of there would leave every later request waiting on a reply that never comes. A delegate rather than a logging abstraction, so that this package keeps its three dependencies and a host can adapt it to whatever it already has.