feature request: add "force" arg to `gd_get`?

To override the local hash looking up to date but the remote data being updated. This happens when someone hasn't pushed changes to the .ind file to the repo.

Relevant for other `{x}_get` functions too

Locate gd_get and the other {x}_get functions, then trace how they decide that the local hash is current before fetching remote data. Add coverage for the force argument and confirm that done means a forced lookup bypasses the local freshness result, including the stated case where .ind changes were not pushed.

Written by the indexing model from the issue text.